Droplet Discharge Device, and Method for Forming Pattern, and Method for Manufacturing Display Device

ABSTRACT

It is an object of the present invention to improve the usability of a material, and to provide a display device which can be manufactured by simplifying the manufacturing process and a manufacturing technique thereof. It is also an object of the invention to provide a technique in which a pattern of a wiring or the like constituting these display devices can be formed to have a desired shape with favorable controllability. One feature of a droplet discharge device of the invention comprises: a discharge means for discharging a composition including a pattern forming material; and a shape means for shaping the shape of the composition before the composition is attached to a formation region, in which the shape means is provided between the discharge means and the formation region.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a droplet discharge device for forminga pattern by discharging (applying) a droplet, to a method for forming apattern, and to a method for manufacturing a display device using themethod thereof.

2. Description of the Related Art

A thin film transistor (hereinafter, referred to as a “TFT”) and anelectronic circuit using the thin film transistor are manufactured bylaminating various types of thin films of a semiconductor, an insulatingmaterial, a conductive material, and the like over a substrate and then,appropriately forming a predetermined pattern with a photolithographytechnique. The photolithography technique means a technique oftransferring a pattern of a circuit or the like formed over a surface ofa transparent flat plane referred to as a photomask by using a materialwhich does not transmit light, onto a targeted substrate by utilizinglight, and the technique has widely been used in the manufacturingprocess of a semiconductor integrated circuit or the like.

In the manufacturing process employing a conventional photolithographytechnique, it is necessary to perform a multi-stage step including lightexposure, developing, baking, peeling, and the like only for treating amask pattern which is formed by using a photosensitive organic resinmaterial referred to as a photoresist. Therefore, as the number of timesof the photolithography step is increased more, the manufacturing costis inevitably increased more. In order to improve such problems asdescribed above, it has been tried to manufacture a TFT by reducing thenumber of the photolithography step (for example, Reference 1: JapanesePatent Laid-Open No. H11-251259).

However, in the technique disclosed in Reference 1, only a part of thephotolithography step which is carried out plural times in TFTmanufacturing process is replaced by a printing method and nocontribution is made to a drastic reduction in the number of steps.Further, a light exposing apparatus to be used for transferring the maskpattern in the photolithography technique transfers a pattern of fromseveral micrometers to 1 micrometer or less by equivalent projectionlight exposure or reduction projection light exposure. It istheoretically difficult for the light exposing apparatus to expose alarge area substrate having a side of more than 1 meter to light all atonce from a technical standpoint.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a technique inwhich, in the manufacturing process of a TFT, an electronic circuitusing the TFT, or a light emitting display device formed by using theTFT, the manufacturing process is simplified by reducing the number oftimes of the photolithography step or by eliminating thephotolithography step itself, and in which a large area substrate havinga side of more than 1 meter can be manufactured with a higher yield atlower cost.

It is also an object of the invention to provide a technique in which apattern of a wiring or the like constituting these display can be formedto have a desired shape with favorable controllability.

The following measures are taken in the invention to solve the problemsof the above-mentioned related art.

One feature of the invention is that at least one or more of patternsrequired to manufacture a display panel, such as a wiring layer, aconductive layer for forming an electrode, or a mask layer for forming apredetermined pattern is/are formed by a method capable of selectivelyforming a pattern, and then, a light emitting display device ismanufactured. A droplet discharge (apply) method (also referred to as aninkjet method, depending on its mode) that can form a conductive layer,an insulating layer, or the like, and then, form into a predeterminedpattern by selectively discharging (applying) a droplet of a compositionmixed for a particular purpose is employed as the method capable ofselectively forming a pattern. In addition, a method capable oftransferring or drawing a pattern, for example, a printing method (amethod for forming a pattern, such as screen printing or offsetprinting) or the like can be also employed.

In the invention, a droplet having a composition, which is attached to aform region by the above-mentioned method is shaped (deformed) to have adesired pattern with a shape (processing) means. When a miniaturizedwire is required, a further thinner wiring pattern can be formed byincluding a discharged droplet in a thin linear shape portion includedin the shape means, and drawing as if drawing a line.

Alternatively, instead of directly attaching a droplet from an outlet toa form region, the shape of the droplet is deformed through a shapemeans (a shape portion), and the droplet is drawn in the form region tohave a desired thickness. In the shape means (the shape portion), theamount of the droplet is adjusted by passing through a thin linearstring or the like, and being scanned in the form region to form aminute wiring. The shape means (the shape portion) may be like a brushin which plural liner strings are bound. The shape is not limited, andit may be a string shape or a plate shape. When a pattern is to beformed over a relatively large area, a shape means (a shape portion)which can attach a droplet to a large area at once may be selected.

According to the invention, regardless the size of an outlet whichdischarge a droplet, a pattern having a desired width can be formed withfavorable controllability.

The shape means and an object for shaping may be formed of an inorganicmaterial, an organic material, or a material in which a skeleton isformed by the bond of silicon and oxygen. The shape means may be alsoformed of a conductive material such as a metal or an insulatingmaterial such as a resin, since it is a means only for processing adroplet. Additionally, it may be formed of fiber or the like.Considering installing in a device, a shape means which is relativelylightweight and easy to process is preferable. When a minute wiringpattern is to be drawn, a nanotube material such as a carbon nanotubecan be used. As an ultrafine carbon fiber formed of a carbon nanotube orthe like, graphite nanofibers, carbon nanofibers, tubular graphite,carbon nanocorn, corn-shaped graphite or the like can be used. As for amaterial for a processing means, a material in which reaction or thelike is not generated depending on a composition included in a dropletto be processed, may be selected.

The display of the invention includes a light-emitting device in which alight emitting element sandwiching an organic matter emittingluminescence referred to as electro luminescence (hereinafter alsoreferred to as “EL”) or a medium including a mixture of an organicmatter and an inorganic matter between electrodes is connected to a TFT;a liquid crystal display device in which a liquid crystal element havinga liquid crystal material is used as a display element; or the like.

According to the invention, a means for improving adhesion (basepretreatment) is performed on a form region when forming a pattern by adroplet discharge method, thereby improving the reliability of a displaydevice.

One feature of the invention is that a display device including asemiconductor film, an insulating film, a mask, and the like in additionto a wiring is formed by using a substance which has an effect ofenhancing adhesion. In a step, when a predetermined pattern is formed bydischarging a droplet including a predetermined composition from a finepore, a substance formed of a high melting point metal is formed as basepretreatment for enhancing the adhesion. Specifically, a wiring materialmixed in a solvent (including a material in which a wiring material (aconductive material) is dissolved or dispersed in a solvent) is formedover a conductive layer formed of a high melting point metal or the endsthereof by an application method or the like, to form a wiring. Forexample, a conductive material mixed in a solvent is discharged over aconductive layer formed of a high melting point metal, or a 3dtransition element by a droplet discharge method. In addition to adroplet discharge method, a conductive material mixed in a solvent maybe formed over the conductive layer formed of a high melting point metalby a spin coating method, a dip method, another application method, aprinting method (a method for forming a pattern, such as screen printingor offset printing).

As a substance used for base pretreatment, titanium oxide (TiO_(x)),strontium titanate (SrTiO₃), cadmium selenide (CdSe), potassiumtantalate (KtaO₃), cadmium sulfide (CdS), zirconia (ZrO₂), niobium oxide(Nb₂O₅), zinc oxide (ZnO), iron oxide (Fe₂O₃), tungsten oxide (WO₃) orthe like can be used.

The substance used for base pretreatment can be formed by a sol-gelmethod such as a dip coating method, a spin coating method, a dropletdischarge method, or an ion plating method, an ion beam method, a CVDmethod, a sputtering method, an RF magnetron sputtering method, a plasmaspray method, or an anodic oxidation method. In addition, the substancedoes not need to have continuity as a film, depending on its formationmethod.

As the above-mentioned high melting point metal or a 3d transitionelement, a material of Ti (titanium), W (tungsten), Cr (chrome), Al(aluminum), Ta (tantalum), Ni (nickel), Zr (zirconium), Hf (hafnium), V(vanadium), Ir (iridium), Nb (niobium), Pd (lead), Pt (platinum), Mo(molybdenum), Co (cobalt), Rh (rhodium), Sc (scandium), Mn (manganese),Fe (iron), Cu (copper) or Zn (zinc), or an oxide, a nitride, or anoxynitride thereof can be used. The conductive layer is formed by aknown method such as a sputtering method, a vapor deposition method, anion implantation method, a CVD method, a dip method, or a spin coatingmethod, preferably, by a sputtering method, a dip method or a spincoating method. In the case where the conductive layer is insulatedlater, it is simple and preferable to form the conductive layer in from0.01 nm to 10 nm thick, and insulate the conductive film due to naturaloxidation.

Alternatively, a method for performing plasma treatment on a formationregion (formation face) is employed as another method. The plasmatreatment is performed with air, oxygen, or nitrogen used as a treatmentgas, with pressure from several tens of Torr to 1000 Torr (133000 Pa),preferably, from 100 Torr (13300 Pa) to 1000 Torr (133000 Pa), morepreferably, from 700 Torr (93100 Pa) to 800 Torr (106400 Pa), that is,atmospheric pressure or pressure in proximity of atmospheric pressure,and a pulse voltage is applied under such conditions. At this time, theplasma density is set from 1×10¹⁰ m⁻³ to 1×10¹⁴ m⁻³, so-called coronadischarge or glow discharge. Surface modification can be performedwithout material dependence by employing plasma treatment using air,oxygen, or nitrogen as a treatment gas. Accordingly, surfacemodification can be performed on any material.

As another alternative method, a substance of an organic materialfunctioning as an adhesive may be formed to improve the adhesion of apattern to be formed by a droplet discharge method with a formationregion thereof. A film formed of one or a plurality of photosensitive ornon-photosensitive organic materials (organic resin materials)(polyimide, acrylic, polyamide, polyimide amide, a resist,benzocyclobutene, or the like), a Low k material having a low dielectricconstant, and the like; a lamination layer thereof; or the like can beused as the material. In addition, a material in which a skeleton isconfigured by the bond of silicon (Si) and oxygen (O) and which containsat least hydrogen as a substituent or which contains at least one offluorine, an alkyl group, and aromatic hydrocarbon as a substituent maybe used. A droplet discharge method or a printing method (a method forforming a pattern, such as screen printing or offset printing) can beemployed as a manufacturing method. A TOF film, an SOG film, or the likeobtained by an application method can be also used.

The above-mentioned step performed for improving adhesion or surfacemodification on a region where a conductive material is formed by usinga droplet discharge method as base pretreatment, may be also performedwhen a conductive material is further formed over a pattern formed byusing a droplet discharge method. As base pretreatment in that case,ultraviolet irradiation treatment which radiates ultraviolet ray isperformed after forming a first conductive layer by a droplet dischargemethod, and then, a second conductive layer may be formed in aprocessing region by a droplet discharge method. For example, afterforming a wide pattern with the use of an outlet having a largediameter, a thin pattern is formed so as to partially overlap with thewide pattern with a shape means according to the invention, therebyforming a minute pattern.

As for the composition to be discharged from the outlet by a dropletdischarge method to form a conductive material (a conductive layer), aconductive material dissolved or dispersed in a solvent is used. Theconductive material corresponds to a fine particle or a dispersantnano-particle of a metal such as Ag, Au, Cu, Ni, Pt, Pd, Ir, Rh, W, orAl, sulfide of a metal such as Cd or Zn, oxide of Fe, Ti, Si, Ge, Zr,Ba, or the like, or silver halide. In addition, it corresponds to indiumtin oxide (ITO), ITSO formed of indium tin oxide and silicon oxide,organic indium, organotin, zinc oxide, titanium nitride, or the likewhich is used as a transparent conductive film. However, as for acomposition to be discharged from the outlet, it is preferable to useany material of gold, silver, and copper, which is dissolved ordispersed in a solvent, taking a specific resistance value intoconsideration. It is more preferable to use silver or copper having alow resistance value. When silver or copper is used, a barrier film maybe additionally provided as a measure for an impurity. A silicon nitridefilm or nickel boron (NiB) can be used as the barrier film.

In addition, a particle in which a conductive material is coated withother conductive materials to be a plurality of layers may be used. Forexample, a three-layer structure particle in which copper is coated withnickel boron (NiB), and then coated with silver may be used. As for suchsolvents, esters such as butyl acetate or ethyl acetate; alcohols suchas isopropyl alcohol or ethyl alcohol; organic solvents such as methylethyl ketone or acetone; or the like may be used. The viscosity of thecomposition is preferably 20 cp or less. This is because the compositionis prevented from drying or the composition is smoothly discharged fromthe outlet. The surface tension of the composition is preferably 40 mN/mor less. However, the viscosity of the composition and the like may beappropriately adjusted in accordance with a solvent to be used and useapplication. For example, the viscosity of a composition in which ITO,organic indium, or organotin is dissolved or dispersed in the solvent isfrom 5 mPa·S to 20 mPa·S, the viscosity of a composition in which silveris dissolved or dispersed in the solvent is from 5 mPa·S to 20 mPa·S,and the viscosity of a composition in which gold is dissolved ordispersed in the solvent is from 5 mPa·S to 20 mPa·S.

In the invention, a conductive layer which constitutes a display devicecan be formed by a droplet discharge method. First, a conductive layerformed with a relatively wide line width (also referred to as a “busline”) such as a gate line, a source line or other lead wiring isdirectly formed by a droplet discharge method. A minute wiring can bedrawn by shaping a conductive layer having a relatively thin line widthsuch as a gate electrode, a source/drain electrodes, and another wiringin a pixel portion which are formed so as to be connected to the sourceline or the gate line as if branching off the source line or the gateline with a shape means according to the invention. According to theinvention, a gate wiring having a line width of from 10 μm or more to 40μm or less, a gate electrode having a line width of from 5 μm or more to20 μm or less, preferably from 0.3 μm or more to 10 μm or less;therefore, a wiring in which the line width of the gate wiring is abouttwice that of the gate electrode can be formed. According to theinvention, requirements of reduction in resistance for flowing largecurrent to the wiring with efficiency and high-speed, and ofminiaturization of a pattern having no disconnection to an electrode canbe both achieved. According to the invention, a further minute wiringcan be formed without being limited to the diameter of an outlet of adroplet.

One feature of a droplet discharge device of the invention comprises: adischarge means for discharging a composition including a patternforming material; and a shape means for shaping the shape of thecomposition before the composition is attached to a formation region, inwhich the shape means is provided between the discharge means and theformation region.

Another feature of a droplet discharge device of the inventioncomprises: a discharge means for discharging a composition including apattern forming material; and a shape means for shaping the shape of thecomposition after the composition is attached to a formation region.

In the above-mentioned structure, the shape means may be provided to bein contact with an outlet of the droplet discharge means, or can beseparately scanned by being provided separately. Additionally, the shapemeans has a shape portion, and various shapes such as a needle shape, acolumnar shape, a stick shape, a string shape, a plate shape, or a tubeshape can be used for a shape of the shape portion.

Another feature of a method for forming a pattern of the invention isthat a composition including a pattern forming material is dischargedtoward a formation region, and a pattern is selectively formed byshaping the shape of the composition before the composition is attachedto the formation region.

Another feature of a method for forming a pattern of the invention isthat a composition including a pattern forming material is dischargedtoward a formation region, and a pattern is selectively formed byshaping the shape of the composition after the composition is attachedto the formation region and before the composition is cured.

In the above-mentioned structure, the shape of the composition is shapedby the shape portion of the shape means. However, when the shape portionhas a narrow shape such as a needle shape or a string shape, a minutepattern can be shaped. On the other hand, when the shape portion has awide shape having relatively a large area such as a columnar shape or aplate shape, a large pattern can be formed at once.

Another feature of a method for manufacturing a display device of theinvention comprises a semiconductor layer, a wiring, and an electrode,in which a composition including a conductive material is dischargedover a formation region, a part of the shape of the composition isshaped, and the composition is selectively enlarged; thereby forming awiring and an electrode.

In the above-mentioned structure, the wiring and the electrode can beformed by a material which constitutes the above-mentioned conductivematerial by a droplet discharge method. The electrode can be used as agate electrode layer, and the width in a channel direction of the gateelectrode layer is from 5 μm or more to 100 μm or less, more preferably,from 0.3 μm or more to 10 μm or less. The amount of the droplet of from0.1 pl or more to 40 pl or less is discharged by a droplet dischargemethod, and a pattern can be formed.

In the above-mentioned structure, the semiconductor layer may be anamorphous semiconductor including a crystalline structure, which isformed by a gas containing hydrogen and a halogen. The semiconductorlayer may be also a non-crystalline semiconductor which is formed of agas containing hydrogen and halogen, or polycrystalline semiconductorformed of a gas containing hydrogen and a halogen element. It ispreferable that the length in a channel direction in a region where theelectrode and the semiconductor layer are intersected is from 5 μm ormore to 100 μm or less, more preferably, from 0.3 μm or more to 10 μm orless. In addition, a TV set in which a display screen image includes theabove-mentioned display device can be manufactured.

A gate insulating layer which can be used in the invention is formed bysequentially laminating a first silicon nitride film, a silicon oxidefilm and a second silicon nitride film. Accordingly, a gate electrodecan be prevented from being oxidized, and a favorable interface with asemiconductor layer to be formed on the upper layer side of the gateinsulating layer can be formed.

One feature of the invention is that a mask used for forming the gateelectrode layer, the wiring layer, and for patterning can be formed by adroplet discharge method. Among patterns required to manufacture thedisplay device, at least one pattern is formed by a method in which thepattern can be selectively formed to manufacture the display device,which achieves the object of the invention.

In addition, an insulating layer to be used as a partition wall or thelike may be formed of an organic material, an inorganic material, or amaterial in which a skeleton is configured by the bond of silicon andoxygen. Since the organic material is superior in the planarity, thefilm thickness does not become extremely thin and disconnection does notoccur in a step portion even when a conductive material is formed later;therefore, it is preferable. In addition, the organic material has a lowdielectric constant. Accordingly, when the organic material is used asan interlayer insulating material of a plurality of wirings, the wiringcapacity is reduced. Then, a multilayer wiring can be formed, and higherefficiency and higher function can be obtained.

On the other hand, a siloxane polymer can be given as a typical exampleof the material in which a skeleton is configured by the bond of siliconand oxygen. Specifically, it is a material in which a skeleton isconfigured by the bond of silicon and oxygen and which contains at leasthydrogen as a substituent or which contains at least one of fluorine, analkyl group, and aromatic hydrocarbon as a substituent. The material isalso superior in planarity and has transparency and heat resistance. Aninsulating material formed of a siloxane polymer can be heat-treated attemperatures of approximately equal to or lower than from 300° C. to600° C. after formation.

According to the invention, patterns of a conductive layer can beseparately formed depending on the line width. Accordingly, in wiringsincluded in a display device, a wiring with low resistance having a wideline and a minute wiring used for a pixel portion or the like can beboth formed to fulfill required function depending on its role.

According to the invention, patterning of a wiring layer or a mask canbe directly performed by a droplet discharge method; therefore, a TFT inwhich the usability of a material is improved and the manufacturingprocess is simplified, and a highly reliable display device usingthereof can be obtained.

These and other objects, features and advantages of the presentinvention will become more apparent upon reading of the followingdetailed description along with the accompanied drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A to 1D show views describing a certain aspect of the presentinvention;

FIG. 2 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 3 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 4 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 5 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 6 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 7 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIGS. 8A to 8C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIGS. 9A to 9C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIGS. 10A to 10C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIGS. 11A to 11C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIGS. 12A to 12C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIGS. 13A to 13C show views describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIG. 14 shows a view describing method for manufacturing a displaydevice of a certain aspect of the invention;

FIG. 15A to 15C show a view describing a method for manufacturing adisplay device of a certain aspect of the invention;

FIG. 16 shows a figure for describing a structure of a droplet dischargedevice to which a certain aspect of the invention can be applied;

FIG. 17 shows electronic devices to which a certain aspect of theinvention is applied;

FIGS. 18A to 18D show electronic devices to which a certain aspect ofthe invention is applied;

FIG. 19 is a block diagram which shows a main structure of an electronicdevice of a certain aspect of the invention;

FIG. 20 is a cross-sectional view which explains a structure example ofan EL display module of a certain aspect of the invention;

FIG. 21 is a cross-sectional view which explains a structure example ofa liquid crystal display module of a certain aspect of the invention;

FIG. 22 is a diagram which explains a circuit structure when a scanningline driver circuit is formed of a TFT in an EL display panel of acertain aspect of the invention;

FIG. 23 is a diagram which explains a circuit structure when a scanningline driver circuit is formed of a TFT in an EL display panel of acertain aspect of the invention (a shift register circuit);

FIG. 24 is a diagram which explains a circuit structure when a scanningline driver circuit is formed of a TFT in an EL display panel of acertain aspect of the invention (a buffer circuit);

FIG. 25 shows a view describing a method for manufacturing a displaydevice of a certain aspect of the invention;

FIGS. 26A to 26F are circuit diagrams for explaining a pixel structureto which an EL display panel of a certain aspect of the invention can beapplied;

FIG. 27 is a top view for explaining an EL display panel of a certainaspect of the invention;

FIG. 28 is an equivalent circuit diagram of an EL display panel which isexplained in FIG. 27;

FIG. 29 is a top view of a display device of a certain aspect of theinvention;

FIG. 30 is a top view of a display device of a certain aspect of theinvention;

FIG. 31 is a top view of a display device of a certain aspect of theinvention;

FIGS. 32A to 32C are cross-sectional views of a display device of acertain aspect of the invention; and

FIGS. 33A to 33C show views describing a method for manufacturing adisplay device of a certain aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment Mode of the present invention will be described below indetail with reference to the accompanying drawings. However, theinvention is not limited to the following description and it is easilyunderstood that various changes and modifications will be apparent tothose skilled in the art, unless such changes and modifications departfrom content and the scope of the invention. Therefore, the invention isnot interpreted with limiting to the description in embodiment modeshown hereinafter Note that, in the structure of the invention describedhereinafter, the same reference numerals denote the same parts or partshaving the same function in different drawings and the explanation willnot be repeated.

FIG. 29 shows a top view of a structure of a display panel according tothe invention. A pixel portion 2701 in which pixels 2702 are arranged ina matrix, a scanning line input terminal 2703, and a signal line inputterminal 2704 are formed over a substrate 2700 having an insulatingsurface. The number of pixels may be provided according to variousstandards. The number of pixels of XGA may be 1024×768×3 (RGB), that ofUXGA may be 1600×1200×3 (RGB), and that of a full-speck high vision tocorrespond thereto may be 1920×1080×3 (RGB).

The pixels 2702 are arranged in a matrix by intersecting a scanning lineextended from the scanning line input terminal 2703 with a signal lineextended from the signal line input terminal 2704. Each pixel 2702 isprovided with a switching element and a pixel electrode connectedthereto. A typical example of the switching element is a TFT. A gateelectrode side of a TFT is connected to the scanning line, and a sourceor drain side thereof is connected to the signal line; therefore, eachpixel can be controlled independently by a signal inputted from outside.

A TFT includes a semiconductor layer, a gate insulating layer, and agate electrode as main components. A wiring connected to one of a sourceregion and a drain region which are formed in the semiconductor layer isconcomitant thereof. A top gate type in which a semiconductor layer, agate insulating layer, and a gate electrode layer are sequentiallyarranged from the substrate side, a bottom gate type in which a gateelectrode layer, a gate insulating layer, and a semiconductor layer aresequentially arranged from the substrate side, and the like are known astypical structures of a TFT. However, any one of the structures may beapplied to the invention.

An amorphous semiconductor (hereinafter also referred to as an “AS”)manufactured by a vapor phase growth method using a semiconductormaterial gas typified by silane or germane or a sputtering method; apolycrystalline semiconductor that is formed by crystallizing theamorphous semiconductor by utilizing light energy or thermal energy; asemi-amorphous (also referred to as microcrystallite ormicrocrystalline, and hereinafter also referred to as an “SAS”)semiconductor; or the like can be used for a material which forms asemiconductor layer.

An SAS is a semiconductor with an intermediate structure between anamorphous structure and a crystal structure (including a single crystaland a polycrystal). This is a semiconductor having a third conditionthat is stable in regard to a free energy, and a crystalline regionhaving a short-range order and lattice distortion is included therein. Acrystalline region of from 0.5 nm to 20 nm can be observed at least in apart of a region in the film. When silicon is contained as the maincomponent, Raman spectrum is shifted to a lower frequency side less than520 cm⁻¹. Diffraction peak of (111) or (220) to be caused from a crystallattice of silicon is observed in X-ray diffraction. At least 1 atomic %or more of hydrogen or halogen is contained to terminate a danglingbond. An SAS is formed by carrying out grow discharge decomposition(plasma CVD) of a silicide gas. In addition to SiH₄, Si₂H₆, SiH₂Cl₂,SiHCl₃, SiCl₄, SiF₄, or the like can be used for the silicide gas. Inaddition, GeF₄ may be mixed. This silicide gas may be diluted with H₂ orH₂ and one or more of the rare gas element of He, Ar, Kr, and Ne. Adilution ratio ranges from 2 times to 1000 times. A pressure rangesapproximately from 0.1 Pa to 133 Pa, and a power frequency ranges from 1MHz to 120 MHz, preferably from 13 MHz to 60 MHz. A substrate heatingtemperature may be 300° C. or lower. It is desirable that an atmosphericconstituent impurity such as oxygen, nitrogen, or carbon is 1×10²⁰ cm⁻¹or less as an impurity element in the film, specifically an oxygenconcentration is 5×10¹⁹/cm³ or less, preferably 1×10¹⁹/cm³ or less.

FIG. 29 shows a structure of a liquid crystal display panel thatcontrols a signal inputting into a scanning line and a signal line by anexternal driver circuit. Furthermore, a driver IC may be mounted on asubstrate 700 by a COG (Chip on Glass) as shown in FIG. 30. In FIG. 30,the substrate 701 is pasted with the sealing substrate 703 using asealing material 702.

Also, a driver IC 707 a, a driver IC 707 b, a driver IC 707 c, a driverIC 705 a, and a driver IC 705 b provided over the substrate 700 areconnected with FPC 704 a, FPC 704 b, FPC 704 c, FPC 706 a, FPC 706 b,respectively. The drive IC may be formed over a monocrystalsemiconductor substrate, or the one in which a circuit is formed of aTFT over a glass substrate.

When a TFT provided in a pixel is formed of an SAS, a scanning linedriver circuit 3702 may be integrally formed over a substrate 3700 asshown in FIG. 31. In FIG. 31, reference numeral 3701 denotes a pixelportion, and driver ICs 3705 a and 3705 b are mounted on a signal linedriver circuit by COG and the signal line driver circuit is connected toFPCs 3704 a and 3704 b.

EMBODIMENT MODE 1

Embodiment mode of the present invention is described with reference toFIGS. 1A to 1D and FIG. 16.

FIGS. 1A to 1D are detail views of a method for forming a pattern of adevice according to the invention. The invention employs a method forforming a pattern by discharging a droplet.

In FIG. 1A, reference numeral 50 denotes a formation region; 11, a headportion; 12 b, control means of a droplet discharge means; and 18, anozzle. Being adjacent to them, reference numeral 10 denotes a shapemeans; 14, a shape portion; 12 a, a control means of the shape means. Adroplet 13 having a pattern formation material discharged from thenozzle 18 by the control means 12 b is attached to the brush-shapedshape portion 14, and formed in a shape like a pattern 15 through theform shape 14 over the formation region 50. By scanning the shape meansand the head portion in a direction 16, the pattern 15 is formed to be alinear shape.

As in this embodiment mode, when the shape portion 14 is made to have aneedle shape in which the diameter is made smaller toward a tipdirection, the size of a droplet discharged from an outlet of the nozzle18 is shaped until it is attached to the formation region 50; therefore,the minute pattern 15 having a further narrower width can be formed. Byscanning the shape portion 14, the amount of a droplet attached to theformation region 50 can be adjusted. Accordingly, the pattern 15 can beformed to have a desired width and shape without depending on thediameter of the nozzle by controlling the shape of the shape portion 14and the scanning speed.

In FIG. 1A, an example in which a droplet is shaped to have a desiredshape with a shape means while it is discharged from an outlet of adroplet of the nozzle until being attached to a formation face is shown.In FIG. 1B, a method for forming a shape before a composition is curedafter discharging a droplet over the formation region is shown.

In FIG. 1B, reference numeral 60 denotes a formation region; 21, a headportion; 22 b, a control means of a droplet discharge means; and 28, anozzle. Being adjacent to these, reference numeral 20 denotes a shapemeans; 24, a shape portion; 22 a, a control means of the shape means. Adroplet having a pattern formation material discharged from the nozzle28 by the control means 22 b is attached to the formation region 60 as adroplet 23. Before the droplet 23 is fully solidified, the shape means20 and the shape portion 24 are moved in a direction 27 by the controlmeans 22 a and scanned over the droplet 23 in a direction 26. At thistime, the shape portion 24 shapes the droplet 23 and a pattern 25 isformed by deforming the shape. A pattern can be freely shaped by theshape portion 24 since the droplet 23 is not fully solidified at thistime.

The pattern 25 can be formed to have a desired width and a shape withoutdepending on the diameter of an outlet of the nozzle by adjusting theshape of the shape portion 24, the scanning speed in the direction 26,the moving distance in the direction 27 and the like.

In this embodiment mode, although a mode in which the shapes of theshape portions 14 and 24 have needle shapes in which the diametersbecome narrower toward the tips, columnar shapes, plate shapes, stingshapes and the like can be appropriately selected according to a desiredpattern shape. When a pattern is to be broadly formed, a spatular shapeform portion may be used so that the area being in contact with adroplet at a time becomes broader toward the tip. Alternatively, a formportion in which a plurality of fine bristles (or strings) are boundlike a brush may be also used.

Then, another shape means methods are shown in FIGS. 1C and 1D. FIGS. 1Cand 1D shows examples in which a shape portion is formed integrally in anozzle. In FIG. 1C, reference numeral 70 denotes a formation region; 30,a head portion; 32, a control means of a droplet discharge means; and38, a nozzle, and a shape portion 34 which is a shape means is providedfor the nozzle 38. The shape portion 34 has a tube shape with space 33therein. A droplet having a pattern formation material discharged fromthe nozzle 38 is controlled through the space 33 inside the shapeportion 34, and is shaped to have the shape of a droplet 31 and attachedto the formation region. The shape of the droplet 31 can be freelycontrolled by the size of the space 33 inside the shape portion 34;therefore a minute pattern can be also formed.

As shown in FIG. 1D, a minute linear pattern 41 can be also formed overa formation region 80 by sequentially discharging a droplet and scanningthe droplet discharge method in a direction 46. A desired pattern can befreely formed without depending on the size of an outlet by controllingthe size of the space 33 inside the shape portion 34 and the scanningspeed. Thus, various patterns can be formed by selecting and providingthe shape of the shape portion 34 as if replacing pen tips. Naturally,FIGS. 1A and 1B can be combined with FIGS. 1C and 1D. A minute patterncan be formed effectively since a pattern can be shaped accurately.

A shape or a material of the shape portion can be freely selectedaccording to a pattern desired to be formed in a form region. Either ahard material or a soft material may be used. A material may be selectedaccording to the viscosity of a material from which a pattern desired tobe shaped is formed. At this time, when a droplet is physically shaped,it is desirable that a material which forms a pattern and a material inthe shape portion do not react with each other. However, a pattern canbe also formed over the formation region by making a material in contactwith the shape portion to change its physicality.

Shape means and the shape portion can formed of silicon oxide, siliconnitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminumoxynitride, or another inorganic material; acrylic acid, methacrylicacid, and a derivative thereof; a heat-resistant polymer such aspolyimide, aromatic polyamide, polybenzimidazole; another organicmaterial; inorganic siloxane including the Si—O—Si bond among compoundsincluding silicon, oxygen and hydrogen formed by using a siloxane systemmaterial as a start material; or an organic siloxane system material inwhich hydrogen over silicon is substituted by an organic group such asmethyl or phenyl. Since it is a means only for shaping a droplet, aconductive material such as a metal or an insulating material such as aresin may be used. Alternatively, fiber or the like may be also used.Considering providing for a device, a material which is relativelylightweight and easy to be shaped is preferable. When a minute wiring orthe like is desired to be drawn, a nanotube material such as a carbonnanotube may be also used. As an ultrafine carbon fiber formed of acarbon nanotube or the like, graphite nano-fiber, carbon nano-fiber,tube-shaped graphite, carbon nano-corn, corn-shaped graphite or the likecan be used.

In the invention, a desired pattern can be freely drawn and formed as ifdrawing a picture with a paint brush or a pen without depending on theshape or the size of an outlet which discharges a droplet over aformation region with a shape means.

EMBODIMENT MODE 2

Embodiment mode according to the present invention is described withreference to FIGS. 2 to 7. FIGS. 8A to 8C, FIGS. 9A to 9C, FIGS. 10A to10C, FIGS. 11A to 11C, FIGS. 12A to 12C and FIGS. 13A to 13C. In moredetail, a method for manufacturing a display device to which theinvention is applied is described. First, a method for manufacturing adisplay device having a channel etch type thin film transistor to whichthe invention is applied is described. Each of FIGS. 2 to 7 correspondsto FIGS. 8A to 8C, FIGS. 9A to 9C, FIGS. 10A to 10C, FIGS. 11A to 11C,FIGS. 12A to 12C and FIGS. 13A to 13C. FIGS. 2 to 7 show top views ofpixel portions of display devices, and FIG. A in FIGS. 8 to 13 showcross-sectional views taken along lines A-A′ in FIGS. 2 to 7. Likewise,FIG. B in FIGS. 8 to 13 show cross-sectional views taken along linesB-B′ in FIGS. 2 to 7, and FIG. C in FIGS. 8 to 13 show cross-sectionalviews taken along lines C-C′ in FIGS. 2 to 7.

A base film 101 which improves adhesion is formed over a substrate 100as base pretreatment. Then, a gate wiring layer 103 is formed as shownin FIG. 2 and FIGS. 8A to 8C. A glass substrate formed of bariumborosilicate glass, alumino borosilicate glass, or the like, a quartzsubstrate, a silicon substrate, a metal substrate, a stainless steelsubstrate, or a heat-resistant plastic substrate which can withstand aprocessing temperature in this process is used as the substrate 100. Inaddition, the surface of the substrate 100 may be polished by a CMPmethod or the like so that it is planarized. Note that an insulatinglayer may be formed over the substrate 100. The insulating layer isformed by using an oxide or nitride material containing silicon by aknown method such as a CVD method, a plasma CVD method, a sputteringmethod, or a spin coating method to be a single layer or a laminationlayer. The insulating layer may not be formed, but it is effective inblocking a contaminant or the like caused by the substrate 100 and thelike. In the case of forming a base layer to prevent contamination fromthe glass substrate, the base film 101 is formed as base pretreatmentfor the gate wiring layer 103 to be formed thereover by a dropletdischarge method.

One mode of a droplet discharge device used for forming a pattern isshown in FIG. 16. Each head 1405 and 1412 of a droplet discharge means1403 is connected to a control means 1407, and is controlled by acomputer 1410, so that a preprogrammed pattern can be drawn. The timingof drawing may be determined based on a marker 1411 that is formed overa substrate 1400, for example. Alternatively, a reference point can bedetermined based on an edge of the substrate 1400. That is detected byan imaging means 1404 such as a CCD, and information on the referencepoint converted into a digital signal by an image processing means 1409.Then, the digital signal is recognized by the computer 1410, and acontrol signal is generated and is transmitted to the control means1407. Naturally, information on a pattern to be formed over thesubstrate 1400 is stored in a storage medium 1408, and a control signalis transmitted to the control means 1407 based on the information, sothat each heads 1405 and 1412 of the droplet discharge means 1403 can beindividually controlled. Reference numeral 1413 denotes a shape meansand, in this embodiment mode, it is controlled and scanned by thecontrol means 1407.

The sizes of the heads 1405 and 1412 are different each other, anddifferent materials can be simultaneously drawn to have differentwidths. Each of a conductive material, an organic or inorganic material,and the like can be discharge from one head and drawn. When a droplet isdrawn over a wide area, for example, an interlayer film, one material issimultaneously discharged from a plurality of nozzles to improve athroughput, and thus, drawing can be performed. Droplets including acomposition discharged from heads 1405 and 1412 are shaped to havedesired patterns by the shape means 1413. In this embodiment mode, theexample in which the heads 1405 and heads 1412 included in the dropletdischarge means 1403 and the shape means 1413 are separately scanned isshown. However, as described in Embodiment Mode 1, the heads may beprovided to be adjacent to each other or to be integrally formed. When alarge-sized substrate is used, the head 1405 can freely scan over thesubstrate in a direction indicated by an arrow, and a region to be drawncan be set freely. Thus, a plurality of the same patterns can be drawnover one substrate.

The base film 101 formed as the base pretreatment in this embodiment canbe formed by a sol-gel method such as a dip coating method, a spincoating method, a droplet discharge method, an ion plating method, anion beam method, a CVD method, a sputtering method, an RF magnetronsputtering method, a plasma thermal spraying method, a plasma spraymethod, or an anodic oxidation method. In addition, the substance doesnot need to have continuity as a film depending on its formation method.A solvent may be baked or dried when it is necessary to be removed inthe case of forming the base film 101 by an application method such as adip coating method or a spin coating method.

The case of forming a TiO_(X) (typically, TiO₂) crystal having apredetermined crystal structure by a sputtering method as the base film101 is described in this embodiment mode. Sputtering is performed usingmetal titanium (a titanium tube) as a target and using an argon gas andoxygen. Further, a He gas may be introduced. TiO_(X) may be formed whileheating a film formation chamber or a substrate provided with an objectto be treated.

The thus formed TiO_(X) may be a very thin film.

Further, the base film 101 formed of a metal material such as Ti(titanium), W (tungsten), Cr (chromium), Ta (tantalum), Ni (nickel), orMo (molybdenum), or oxide thereof may be formed by a sputtering method,an evaporation method or the like.

The base film 101 may be formed to be from 0.01 nm to 10 nm inthickness. It may be formed to be very thin and need not necessarilyhave a layer structure. When the base film has conductivity since highmelting point metal material, or a 3d transition element is used, it ispreferable to carry out either of the following two steps on the basefilm which is in except for a conductive layer formation region.

As the first method, the base film 101 which is not overlapped with thegate wiring layer 103 is insulated; thereby forming an insulating layer.In other words, the base film 101 which is not overlapped with the gatewiring layer 103 is oxidized and insulated. When the base film 101 isoxidized and insulated in this way, it is preferable to form the basefilm 101 to be from 0.01 nm to 10 nm in thickness; thus, the base filmcan be easily oxidized. Note that oxidization may be performed byexposing to an oxygen atmosphere or by performing heat treatment.Additionally, an oxygen plasma method, an O₃ oxidation method, a UV-O₃oxidation method or the like can be also used.

As the second method, a formation region of the gate wiring layer 103 (aregion over which a composition including a conductive material isdischarged) is selectively formed. The base film 101 may be selectivelyformed over a substrate using a droplet discharge method, or the basefilm 101 may be formed over the entire face followed by being etched andremoved selectively using the gate wiring layer 103 as a mask. When thisstep is employed, there is no limitation on a thickness of the base film101.

Alternatively, a method for performing plasma treatment on a formationregion (formation face) can be employed as another base pretreatment.The plasma treatment is performed with air, oxygen, or nitrogen used asa treatment gas, with pressure from several tens of Torr to 1000 Torr(133000 Pa), preferably, from 100 Torr (13300 Pa) to 1000 Torr (133000Pa), more preferably, from 700 Torr (93100 Pa) to 800 Torr (106400 Pa),that is, atmospheric pressure or pressure in proximity of atmosphericpressure, and a pulse voltage is applied under such conditions. At thistime, plasma density is set from 1×10¹⁰ m⁻³ to 1×10¹⁴ m⁻³, so-calledcorona discharge or glow discharge. Surface modification can beperformed without material dependence by employing plasma treatmentusing air, oxygen, or nitrogen as a treatment gas. Accordingly, surfacemodification can be performed on any material.

As another method, a substance of an organic material functioning as anadhesive may be formed to improve the adhesion of a pattern to be formedby a droplet discharge method with a formation region thereof. Anorganic material (an organic resin material) (polyimide or acrylic) or amaterial in which a skeleton is configured by the bond of silicon (Si)and oxygen (O), and which contains at least hydrogen as a substituent,or which contains at least one of fluorine, an alkyl group, and aromatichydrocarbon as a substituent may be used.

The gate wiring layer 103 is formed by a droplet discharge method (seeFIG. 2 and FIGS. 8A to 8C). In the invention, among conductive layersconfiguring a display device, a gate wiring layer or a capacitor wiringlayer which are across between pixels and are formed with relativelywide line widths, and a gate electrode layer formed with a relativelynarrow line width within a pixel, and the like are separately formed. Byforming a conductive layer having a wide line width such as a gatewiring layer or a capacitor wiring layer first by adjusting the diameterof an outlet, a gate wiring layer and a capacitor wiring layer whichhave high-reliability and low resistance can be formed withoutdisconnection or the like.

The gate wiring layer 103 is formed by using a droplet discharge means.The droplet discharge means is a general term for the one having a meansof discharging a droplet such as a nozzle having an outlet of acomposition or a head equipped with one nozzle or plural nozzles. Thediameter of the nozzle included in the droplet discharge means is set inthe range of from 0.02 μm to 100 μm (favorably, 30 μm or less) and theamount of the composition to be discharged from the nozzle is set in therange of from 0.001 pl to 100 pl (favorably, 0.1 pl or more to 40 pl orless, more favorably, 10 pl or less). The amount of the composition tobe discharged increases in proportion to the size of the diameter of thenozzle. Further, it is preferable that the distance between an object tobe processed and the outlet of the nozzle is as short as possible inorder to drop the droplet on a desired position. Favorably, the distanceis set approximately in the range of about from 0.1 mm to 3 mm (morefavorably, 1 mm or less).

As for the composition to be discharged from the outlet, a conductivematerial dissolved or dispersed in a solvent is used. The conductivematerial corresponds to a fine particle or a dispersant nano-particle ofmetal such as Ag, Au, Cu, Ni, Pt, Pd, Ir, Rh, W, or Al, sulfide of metalsuch as Cd or Zn, oxide of Fe, Ti, Si, Ge, Zr, Ba, or the like, orsilver halide. In addition, it also corresponds to indium tin oxide(ITO), ITSO formed of indium tin oxide and silicon oxide, organicindium, organotin, zinc oxide, titanium nitride, or the like which isused as a transparent conductive film. However, as for compositions tobe discharged from the outlet, it is preferable to use any material ofgold, silver, and copper, which is dissolved or dispersed in a solvent,taking a specific resistance value into consideration. It is morepreferable to use silver or copper having a low resistance value. Whensilver or copper is used, a barrier film may be additionally provided asa measure for an impurity. A silicon nitride film or nickel boron (NiB)can be used as the barrier film.

In addition, a particle in which a conductive material is coated withother conductive materials to be a plurality of layers may be used. Forexample, a three-layer structure particle in which copper is coated withnickel boron (NiB), which is further coated with silver may be used. Asfor such solvents, esters such as butyl acetate and ethyl acetate;alcohols such as isopropyl alcohol and ethyl alcohol; organic solventssuch as methyl ethyl ketone and acetone; or the like may be used. Theviscosity of the composition is preferably 20 mPa·S or less. This isbecause the composition is prevented from drying or the composition issmoothly discharged from the outlet. The surface tension of thecomposition is preferably 40 mN/m or less. However, the viscosity of thecomposition and the like may be appropriately adjusted in accordancewith a solvent to be used and use application. For example, theviscosity of a composition in which ITO, organic indium, or organotin isdissolved or dispersed in the solvent may be set from 5 mPa·S to 20mPa·S, the viscosity of a composition in which silver is dissolved ordispersed in the solvent may be set from 5 mPa·S to 20 mPa·S, and theviscosity of a composition in which gold is dissolved or dispersed inthe solvent may be set from 5 mPa·S to 20 mPa·S.

The conductive layer may be formed by laminating a plurality ofconductive materials. In addition, the conductive layer may be formed bya droplet discharge method using silver as a conductive material;thereafter, it may be plated with copper or the like. Plating may beperformed by electroplating or a chemical (electroless) plating method.Plating may be performed by soaking a substrate surface into a containerfilled with a solution having a plating material. A solution having aplating material may be applied so that the solution flows over thesubstrate surface with the substrate placed obliquely (or vertically).When the plating is performed by applying a solution with the substrateplaced vertically, there is an advantage of miniaturizing a processapparatus.

The diameter of a particle of the conductive material is preferably assmall as possible for the purpose of preventing clogged nozzles andmanufacturing a high-definition pattern, although it depends on thediameter of each nozzle, a desired shape of a pattern, and the like.Preferably, the diameter of the particle of the conductive material is0.1 μm or less. The composition is formed by a known method such as anelectrolyzing method, an atomizing method, a wet reducing method, or thelike, and the particle size thereof is typically about from 0.01 μm to10 μm. However, when a gas evaporation method is employed, ananomolecule protected with a dispersant is minute, about 7 nm. Wheneach surface of particles is covered with a coating, the nanoparticlesdo not cohere in the solvent and are uniformly dispersed in the solventat a room temperature, and show a property similar to that of liquid.Accordingly, it is preferable to use a coating.

When the step of discharging the composition is performed under lowpressure, the solvent of the composition is evaporated during a periodfrom discharging the composition until the composition lands on anobject to be processed, and thus, later steps of drying and baking thecomposition can be both omitted. It is preferable to perform the stepunder low pressure, since an oxide film or the like is not formed on thesurface of the conductive material. After discharging the composition,either or both steps of drying and baking is/are performed. Each step ofdrying and baking is a step of heat treatment. For example, drying isperformed for three minutes at 100° C. and baking is performed for from15 minutes to 60 minutes at temperatures of from 200° C. to 350° C.,each of which has a different purpose, temperature, and period. Thesteps of drying and baking are performed at normal pressure or under lowpressure by laser light irradiation, rapid thermal annealing, a heatingfurnace, or the like. Note that the timing of the heat treatment is notparticularly limited. The substrate may be heated to favorably performthe steps of drying and baking. The temperature of the substrate at thetime depends on a material of the substrate or the like, but it istypically from 100° C. to 800° C. (preferably, from 200° C. to 350° C.).According to the steps, nanoparticles are made in contact with oneanother and fusion and welding are accelerated by hardening andshrinking a peripheral resin as well as evaporating the solvent in thecomposition or chemically removing the dispersant.

A continuous wave or pulsed wave gas laser or solid laser may be usedfor laser light irradiation. An excimer laser, a YAG laser, and the likecan be given as the gas laser, and a laser using a crystal of YAG orYVO₄ which is doped with Cr, Nd, or the like can be given as the solidlaser. Note that it is preferable to use a continuous wave laser inrelation to the absorptance of laser light. Moreover, a so-called hybridlaser irradiation method which combines a pulsed wave and a continuouswave may be used. However, it is preferable that the heat treatment bylaser light irradiation is instantaneously performed within severalmicroseconds to several tens of seconds so that the substrate 100 is notdamaged, depending on heat resistance of the substrate 100. Rapidthermal annealing (RTA) is carried out by raising the temperaturerapidly and heating for several microseconds to several minutes using aninfrared lamp or a halogen lamp emitting light of from ultraviolet toinfrared in an inert gas atmosphere. Since the treatment is performedinstantaneously, only a thin film on a top surface can be substantiallyheated and a lower layer film is not affected. In other words, even asubstrate having low heat resistance such as a plastic substrate is notaffected.

In addition, the above-described step of forming the base film 101 iscarried out as base pretreatment for a conductive layer to be formed byusing a droplet discharge method; however, this treatment step may becarried out also after forming the gate wiring layer 103.

After forming the gate wiring layer 103 by discharging a composition bya droplet discharge method, the surface may be planarized by pressing itwith pressure to enhance its planarity. As a pressing method,projections may be smoothed by scanning a roller-shaped object on thesurface, or the surface may be vertically pressed with a flatplate-shaped object. Heat treatment may be performed at the time ofpressing. Alternatively, a projection portion of the surface may beremoved with an air knife by softening or melting the surface with asolvent or the like. A CMP method may be also used for polishing thesurface. This step may be applied for planarizing a surface whenprojections are generated by a droplet discharge method.

Then, a gate electrode layer 104 and a gate electrode layer 105 areformed. The gate electrode layer 104 is formed in contact with the gatewiring layer 103 (see FIG. 3). The gate electrode layer 104 can beshaped by forming the gate wiring layer 103, and then, by drawing aminute wiring with a shape means 90 of the invention. In this embodimentmode, after forming the gate wiring layer 103, a part of the gate wiringlayer is expanded with a shape portion included in the shape means 90before the gate wiring layer 103 is fully solidified, thereby beingformed as the gate electrode layer 104 (see FIGS. 9A to 9C). In thisway, when the gate wiring layer 103 is formed integral with the gateelectrode layer 104 within one layer, they can be formed withoutboundary resulting in lower resistance. On the other hand, the gateelectrode layer 105 is shaped by newly discharging a conductive materialand forming the material so as to have a thin line with a shape means91. Needless to say, the gate electrode layer 104 may be also shaped bynewly discharging a conductive material with a shape means without beingformed integrally with the gate wiring layer 103, in the same manner asthe gate wiring layer 105. In this case, the above-mentioned basepretreatment may be also performed on a formation region where the gateelectrode layers 104 and 105 are formed. The gate electrode layer 104may be formed after performing ultraviolet irradiation treatment as thebase pretreatment on a region where the gate wiring layer 103 and thegate electrode layer 104 are in contact with each other in order toenhance adhesion. According to the invention, the line width of the gatewiring layer is formed to be 10 μm or more to 40 μm or less, the linewidth of the gate electrode layer is formed to be 5 μm or more to 20 μmor less, preferably 0.3 μm or more and 10 μm or less; therefore, awiring in which the line width of the gate wiring layer is twice that ofthe gate electrode layer.

The gate wiring layer 103 and the gate electrode layers 104 and 105 maybe simultaneously formed as well. In that case, shape means havingdifferent shape portions are respectively installed in each of aplurality of heads included in the droplet discharge device, and thegate wiring layer 103 and the gate electrode layers 104 and 105 aresimultaneously formed by scanning the shape means once. For example,only a nozzle is scanned in a region where the gate wiring layer 103 isformed, and a nozzle head installed with a shape means having a shapeportion so as to shape a minute pattern is scanned in a region where thegate electrode layers 104 and 105 are formed. A conductive material iscontinuously discharged from an outlet which forms the gate wiring layer103, and a conductive material is discharged from an outlet which formsthe gate electrode layers 104 and 105 when the head is scanned in theform region, and shaped with a shape means. Patterns having differentline widths can be formed even in this way, and a throughput can beimproved.

Subsequently, a gate insulating layer 106 is formed over the gateelectrode layers 104 and 105 (see FIG. 4 and FIGS. 10A to 10C). The gateinsulating layer 106 may be formed of a known material such as an oxideor nitride material of silicon, and may be a lamination layer or asingle layer. In this embodiment mode, it may be a lamination layer ofthree layers of a silicon nitride film, a silicon oxide film, and asilicon nitride film, or may be a single layer of them or of a siliconoxynitride film, or a lamination layer of two layers. A silicon nitridefilm having minute film quality is preferably used. In the case of usingsilver, copper, or the like for the conductive layer formed by a dropletdischarge method, and forming a silicon nitride film or a NiB filmthereover as a barrier film, the silicon nitride film or the Ni film iseffective in preventing an impurity from diffusing and in planarizingthe surface. Note that a rare gas element such as argon is preferablyincluded in a reactive gas and is preferably mixed in the insulatingfilm to be formed in order to form a minute insulating film with fewgate leak current at a low film-formation temperature.

Then, semiconductor layers are formed. The semiconductor layers havingone conductivity type may be formed if necessary. In this embodimentmode, N-type semiconductor layers 109 and 110 are laminated assemiconductor layers having one conductivity type with semiconductorlayers 107 and 108 (see FIG. 4 and FIG. 10A to 10C). Additionally, anNMOS structure of an N-channel type TFT by forming an N-typesemiconductor layer, a PMOS structure of a P-channel type TFT by forminga P-type semiconductor layer, and a CMOS structure of an N-channel typeTFT and a p-channel TFT can be manufactured. An N-channel type TFT and aP-channel type TFT can be also formed by adding an element which impartsconductivity by doping to form an impurity region in the semiconductorlayers in order to impart conductivity.

The semiconductor layers may be formed with a known method (a sputteringmethod, an LPCVD method, a plasma CVD method or the like). Although amaterial for the semiconductor layers are not limited, they may bepreferably formed of silicon, a silicon germanium (SiGe) alloy or thelike.

As a material of the semiconductor layers, an amorphous semiconductor(hydrogenated amorphous silicon as a representative example) or acrystalline semiconductor (polysilicon as a representative example) isused. Examples of polysilicon include a so-called high-temperaturepolysilicon which uses, as a main material, polycrystalline silicon tobe formed through process temperatures of 800° C. or higher, so-calledlow-temperature polysilicon which uses, as a main material,polycrystalline silicon to be formed at process temperatures of 600° C.or lower and crystalline silicon which is crystallized by adding, forexample, an element which promotes crystallization.

Further, as other substances, a semi-amorphous semiconductor or asemiconductor containing a crystalline phase in a part of asemiconductor film can be also used. The term “semi-amorphoussemiconductor” herein means a semiconductor having an intermediatestructure of an amorphous structure and a crystalline structure(including single crystals and poly-crystals) and having a stable thirdstate with respect to free energy, and is a crystalline having ashort-range order and a lattice distortion. Typically, it is asemiconductor layer, including silicon as a main component, with alattice distortion, in which Raman spectrum is shifted to a lowfrequency side from 520 cm⁻¹. Further, at least 1% by atom of hydrogenor a halogen is contained therein to terminate a dangling bond. On thisoccasion, such semiconductor as described above is referred to as asemi-amorphous semiconductor (hereinafter, referred to “SAS” in short).The SAS is also referred to as a so-called microcrystal semiconductor(microcrystalline silicon as a representative example).

The SAS can be obtained by decomposing a silicide gas by means of glowdischarge (plasma CVD). As for a representative silicide gas, SiH₄ ismentioned. As for other gases, Si₂H₆, SiH₂Cl₂, SiHCl₃, SiCl₄, SiF₄ andthe like can be used. Additionally, GeF₄ and F₂ can be mixed. Formationof the SAS can be facilitated by using these silicide gases diluted withhydrogen or a mixture of hydrogen and at least one rare gas of helium,argon, krypton and neon. A dilution ratio of hydrogen to the silicidegas is, for example, preferably in the range of from 2 times to 1000times in terms of flow volume ratio. Although the formation of the SASby glow discharge decomposition is preferably performed under lowpressure, the formation can be also performed under atmospheric pressureby utilizing an electric discharge. As a representative example, theformation may be performed in the pressure range of from 0.1 Pa to 133Pa. A power supply frequency for generating the glow discharge is in therange of from 1 MHz to 120 MHz and preferably, in the range of from 13MHz to 60 MHz. A high-frequency power supply may be appropriately set. Atemperature for heating the substrate is preferably 300° C. or lower andthe temperature in the range of from 100° C. to 200° C. is alsopermissible. As for impurity elements to be incorporated mainly at thetime of forming a film, an impurity derived from an atmosphericcomponent such as oxygen, nitrogen or carbon is preferably used inconcentrations of 1×10²⁰ cm⁻³ or less and, particularly, theconcentration of oxygen is 5×10¹⁹ cm⁻³ or less and preferably 1×10¹⁹cm⁻³ or less. Further, stability of the SAS can be enhanced by promotingthe lattice distortion through allowing a rare gas element such ashelium, argon, krypton or neon to be contained, to thereby obtain afavorable SAS. An SAS layer formed of a hydrogen system gas may belaminated over an SAS layer formed of a fluorine-based gas as asemiconductor layer.

When a crystalline semiconductor layer is used as the semiconductorlayer, a known method (a laser crystallization method, a heatcrystallization method, a heat crystallization method using an elementpromoting crystallization such as nickel, or the like) may be employedas a method for manufacturing the crystalline semiconductor layer. Inthe case of not introducing an element promoting crystallization,hydrogen is released until hydrogen concentration contained in anamorphous silicon film becomes 1×10²⁰ atoms/cm³ or less by heating theamorphous silicon film for one hour at a temperature of 500° C. innitrogen atmosphere before irradiating the amorphous silicon film withlaser light. This is because the amorphous silicon film containing muchhydrogen is damaged when it is irradiated with laser light.

There is no particular limitation on a method for introducing a metalelement into the amorphous semiconductor layer as long as it is a methodcapable of making the metal element exist on the surface of or insidethe amorphous semiconductor layer. For example, a sputtering method, aCVD method, a plasma treating method (including a plasma CVD method), anadsorption method, or a method for applying a metal salt solution can beemployed. Among them, the method using a solution is simple and easy andis useful in terms of easy concentration adjustment of the metalelement. It is preferable that an oxide film is formed by UV lightirradiation in oxygen atmosphere, a thermal oxidation method, treatmentwith ozone water or hydrogen peroxide including a hydroxyl radical, orthe like in order to improve wettability on the surface of the amorphoussemiconductor layer and to spread an aqueous solution over the entiresurface of the amorphous semiconductor layer.

In addition, heat treatment and laser light irradiation may be combinedto crystallize the amorphous semiconductor layer. The heat treatment andthe laser light irradiation may be independently performed plural times.

A crystalline semiconductor layer may be also formed directly over thesubstrate with a linear plasma method. Alternatively, a crystallinesemiconductor layer may be also selectively formed over a substrate witha linear plasma method.

An organic semiconductor using an organic material may be used as asemiconductor. A low molecular weight material, a high molecular weightmaterial, or the like is used for the organic semiconductor, and inaddition, a material such as an organic pigment, a conductive highmolecular weight material can be used.

In this embodiment mode, an amorphous semiconductor is used as asemiconductor. A semiconductor layer is formed and then, an N-typesemiconductor layer is formed with a plasma CVD method or the like as asemiconductor layer having one conductivity type.

Then, the semiconductor layer and the N-type semiconductor layer aresimultaneously pattern-processed by using a mask including an insulatingmaterial such as a resist or polyimide to from the semiconductor layers107 and 108, and the N-type semiconductor layers 109 and 110 (see FIG. 4and FIGS. 10A to 10C). The mask can be formed by selectively discharginga composition. A resin material such as an epoxy resin, an acrylicresin, a phenol resin, a novolac resin, a melamine resin or an urethaneresin is used for the mask. The mask is formed by a droplet dischargemethod by using an organic material such as benzocyclobutene, parylene,flare or polyimide having transmitting properties; a compound materialformed by polymerization of a siloxane system polymer; a compositionmaterial containing a water-soluble homopolymer and a water-solublecopolymer; or the like. Alternatively, a commercially available resistmaterial including a photosensitive agent may be also used and, forexample, a typical positive type resist such as a novolac resin and anaphthoquinonediazide compound which is a photosensitive agent, anegative type resist such as a base resin, diphenylsilanediol, an acidgeneration agent or the like, may be also used. The surface tension andviscosity of any material is appropriately adjusted by adjusting thesolvent concentration or adding a surface-active agent.

A mask including an insulating material such as a resist, polyimide orthe like is formed again by using a droplet discharge method, and athrough-hole 145 is formed in a part of the gate insulating layer 106 byetching-processing. Thus, a part of the gate electrode layer 105 whichis disposed under the gate insulating layer 105 is exposed. Eitherplasma etching (dry etching) or wet etching may be adopted for theetching-process; however, plasma etching is suitable for processing alarge area substrate. As the etching gas, a fluorine-based gas or achlorine-based gas such as CF₄, NF₃, Cl₂, BCl₃ may be used, and an inertgas such as He or Ar may be appropriately added. When etching-processingof atmospheric pressure electric discharging is adopted, local electricdischarging is possible; therefore, a mask layer is not necessarilyformed over the entire surface of the substrate.

After removing the mask, a source wiring layer 118 and a power supplyline 119 are formed by a droplet discharge method (see FIG. 5 and FIGS.11A to 11C). The step of forming the source wiring layer 118 and thepower supply line 119 can be also performed as the step of forming theabove-mentioned gate wiring layer 103.

As a conductive material to form the source wiring layer 118 and thepower supply line 119, a composition which mainly contains a particle ofa metal such as Ag (silver), Au (gold), Cu (copper), W (tungsten), Al(aluminum) can be used. Alternatively, indium tin oxide (ITO), ITSOwhich includes indium tin oxide and silicon oxide, organic indium,organotin, zinc oxide, titanium nitride and the like, which havelight-transmitting properties may be combined.

Source or drain electrode layers 111, 113, 115 and 116, and a conductivelayer 112 are formed by discharging a composition which includes aconductive material, and shaped by a shape means. Then, using the sourceor drain electrode layers 111, 113, 115 and 116 as a mask, the N-typesemiconductor layer is pattern-processed (see FIG. 6 and FIGS. 12A to12C). Although it is not shown, the above-mentioned base pretreatmentstep in which a TiO_(x) film or the like is selectively formed in theregion where the source or drain electrode layers 111, 113, 115 and 116,and the conductive layer 112 are formed before forming the source ordrain electrode layers 111, 113, 115 and 116, and the conductive layer112. Thus, the conductive layer can be formed to have preferableadhesion.

The above-mentioned step of forming the base film is performed as basepretreatment for the conductive layer which is formed by using a dropletdischarge method, and this treatment step may be also performed afterforming the conductive layer. According to the step, reliability of thedisplay device is also enhanced since the adhesion of an interlayer isimproved.

The source or drain electrode layers 111 and 115, and the conductivelayer 112 are formed to be in contact with the source wiring layer 118and the power supply line 119 which are formed before; therefore, thesource or drain electrode layers 111 and 115, and the conductive layer112 may be shaped integrally with the source wiring layer 118 and thepower supply line 119 by using a shape means as in the case of formingthe gate electrode layers 104 and 105. In this embodiment mode, thesource or drain electrode layer 111 is formed by the shape means beforethe source wiring layer 118 is fully cured, and the conductive layer 112and the source or drain electrode layer 115 are formed by the shapemeans before the power supply line 119 is cured. When a material such asan extra fine nanotube is used for a shape portion, a further minutepattern can be formed.

In the through-hole 145 formed in the gate insulating layer 106, thesource or drain electrode 116 and the gate electrode layer 105 areelectrically connected to each other. The conductive layer 112 forms acapacitor element. As a conductive material which forms the source ordrain electrode layers 111, 113, 115 and 116, and the conductive layer112, a composition which mainly contains a particle of a metal such asAg (silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum) canbe used. Alternatively, indium tin oxide (ITO) having light-emittingproperties, ITSO which includes indium tin oxide and silicon oxide,organic indium, organotin, zinc oxide, titanium nitride and the like maybe combined.

In the step of forming the through-hole 145 in a part of the gateinsulating layer 106, the through-hole 145 may be formed by using thesource or drain electrode layers 111, 113, 115 and 116, and theconductive layer 112 as a mask after forming the source or drainelectrode layers 111, 113, 115 and 116, and the conductive layer 112.Then, a conductive layer is formed in the through-hole 145 toelectrically connect the source or drain electrode layer 116 and thegate electrode layer 105. In this case, there is an advantage that thestep is simplified.

Subsequently, a composition including a conductive material isselectively discharged over the gate insulating layer 106 to form afirst electrode layer 117 (see FIG. 7 and FIGS. 13A to 13C). When lightis emitted from the substrate 100 side, or a transmissive EL panel ismanufactured, the first electrode layer 117 may be formed and baked byforming a predetermined pattern with a composition which contains indiumtin oxide (ITO), indium tin oxide containing silicon oxide (ITSO), zincoxide (ZnO), tin oxide (SnO₂) or the like.

Preferably, the first electrode layer 117 is formed of indium tin oxide(ITO), indium tin oxide containing silicon oxide (ITSO), zinc oxide(ZnO) or the like by a sputtering method. More preferably, indium tinoxide containing silicon oxide is used by a sputtering method by using atarget in which from 2 weight percent to 10 weight percent of siliconoxide is contained in ITO. In addition to this, an oxide conductivematerial which contains silicon oxide and in which from 2% to 20% ofzinc oxide (ZnO) is mixed in indium oxide may be used. After forming thefirst electrode layer 117 by a sputtering method, the first electrodelayer 117 may be formed to have a desired pattern by etching by forminga mask layer with the use of a droplet discharge method. In thisembodiment mode, the first electrode layer 117 is formed of a conductivematerial having light-transmitting properties by a droplet dischargemethod, and specifically, it is formed by using indium tin oxide andITSO including ITO and silicon oxide. Although it is not shown, aTiO_(x) film may be formed in a region where the first electrode layer117 is to be formed to perform base pretreatment in the same manner whenthe gate insulating layer 103 is formed. According to the basepretreatment, adhesion is improved and the first electrode layer 117 canbe formed to have a desired pattern.

In this embodiment mode, an example in which the gate insulating layeris formed of a three-layer, namely, a silicon nitride film, a siliconoxynitride (silicon oxide film), silicon nitride film, which includessilicon nitride is previously mentioned. As a preferable structure, thefirst electrode layer 117 including indium tin oxide containing siliconoxide is formed to be closely in contact with the insulating layerincluding silicon nitride which is included in the gate insulating layer106. Accordingly, an effect in which a ratio of light emitted from anelectroluminescent layer to the exterior can be increased, is obtained.The gate insulating layer is sandwiched between the gate wiring layer orthe gate electrode layer and the first electrode layer, and can alsofunction as a capacitor element.

When a reflective type EL display panel is manufactured in the case of astructure in which emitted light is emitted to the opposite side of thesubstrate 100 side, a composition which mainly contains particles of ametal such as Ag (silver), Au (gold), Cu (copper), W (tungsten), or Al(aluminum) can be used. Alternatively, the first electrode layer 117 maybe formed by forming a transparent conductive film or a conductive filmhaving light reflectivity by a sputtering method, forming a mask patternby a droplet discharge method, and then combining etching-processing.

The first conductive layer 117 may be cleaned and polished by a CMPmethod or by cleaning with polyvinyl alcohol-based porous body so thatthe surface of the first conductive layer 117 is made flat. In addition,after polishing with the use of a CMP method, ultraviolet irradiation oroxygen plasma treatment may be performed on the surface of the firstelectrode layer 117.

According to the above-mentioned steps, the substrate 100 having a TFTof a bottom gate type (also referred to as “a reverse stagger type”) anda TFT for a display panel to which a pixel electrode is connected, iscompleted. The TFT in this embodiment mode is a channel etch type.

Subsequently, an insulating layer (also referred to as a partition wallor a bank) 121 is selectively formed (see FIGS. 33A to 33C). Theinsulating layer 121 is formed to have an opening over the firstinsulating layer 117. In this embodiment mode, the insulating layer 121is formed over the entire surface, and etched and patterned by using amask of a resist or the like. When the insulating layer 121 is formed byusing a droplet discharge method or a printing method which can form theinsulating layer 121 directly and selectively, patterning by etching isnot necessarily required. The insulating layer 121 can be also shaped tohave a desired shape with a shape means according to the invention.Productivity is improved by selecting the shape of the shape portionsuch as a columnar shape or a plate shape like a spatular shapeaccording to a dimension of the form region of the insulating layer 121.

The insulating layer 121 can be formed of silicon oxide, siliconnitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminumoxynitride or another inorganic insulating material; acrylic acid,methacrylic acid, or a derivative thereof; a heat-resistant polymer suchas polyimide, polybenzimidazole; inorganic siloxane containing theSi—O—Si bond among a composition including silicon, oxygen and hydrogen,which is formed by using a siloxane system material as a start material;or an organic siloxane-based insulating material in which an organicgroup such as methyl or phenyl is substituted for hydrogen over silicon.The insulating layer 121 may be also formed by using a photosensitivematerial such as acrylic or polymide, or a non-photosensitive material.

After forming the insulating layer 121 by discharging a composition by adroplet discharge method, the surface may be pressed with pressure toplanarize in order to enhance its planarity. As a pressing method,projections may smoothed the projections by scanning a roller-shapedobject, or the surface may be vertically pressed with a flatplate-shaped object. Alternatively, a projection portion of a surfacemay be removed with an air knife by softening or melting the surfacewith a solvent or the like. A CMP method may be also used for polishingthe surface. This step may be applied for planarizing a surface whenprojections are generated by a droplet discharge method. When planarityis enhanced according to the step, display irregularity or the like of adisplay panel can be prevented; therefore, a high-definition image canbe displayed.

A light emitting element is formed over the substrate 100 having a TFTfor a display panel (see FIGS. 33A to 33C).

Before forming an electroluminescent layer 122, moisture in theinsulating layer 121 or adsorbed on its surface is removed by performingheat treatment at a temperature of 200° C. under atmospheric pressure.It is preferable to perform heat treatment at temperatures of from 200°C. to 400° C., preferably from 250° C. to 350° C. under low pressure,and to form the electroluminescent layer 122 without being exposed toatmospheric air by a vacuum evaporation method or a droplet dischargemethod which is performed under low pressure.

As the eletcroluminescent layer 122, materials each indicates theluminescence of red (R), green (G) and blue (B) is selectively formed byan evaporation method using an evaporation mask or the like for each.The materials (low molecular weight materials or high molecular weightmaterials) each indicates luminescence red (R), green (G) and blue (B)can be formed by a droplet discharge method in the same manner as acolor filter. This case is preferable since separate coloring of RGB canbe carried out even without using a mask. Then, a second electrode layer123 is laminated over the electroluminescent layer 122 to complete adisplay device having a display function using a light emitting element(see FIGS. 33A to 33C). In this embodiment mode, an EL (light emitting)display device is completed since an EL (light emitting) element is usedfor a display element; however, when a liquid crystal display elementusing a liquid crystal material of a display element is used, a liquidcrystal display device can be completed.

Although it is not shown, it is effective to provide a passivation filmso as to cover the second electrode layer 123. As the passivation film,a single layer of an insulating film containing silicon nitride (SiN),silicon oxide (SiO₂), silicon oxynitride (SiON), silicon nitride oxide(SiNO), aluminum nitride (AlN), aluminum oxynitride (AlON), aluminumnitride oxide which has more nitrogen content than oxygen content,aluminum oxide, diamond like carbon (DLC) or a nitrogen-containingcarbon film (CN_(x)), or a lamination layer in which the insulatingfilms are combined can be used. For example, a lamination layer such asa nitrogen-containing carbon film (CN_(x)) and silicon nitride (SiN) oran organic material can be used, or a lamination layer of a polymer suchas a styrene polymer may be used. Alternatively, a material which has askeleton formed by the bond of silicon (Si) and oxygen (O), and whichincludes at least hydrogen as a substituent, or at least one offluorine, alkyl group, and aromatic hydrogen as a substituent may bealso used.

At this time, it is preferable to use a film having preferable coverageas the passivation film, and a carbon film, particularly, a DLC film iseffective. A DLC film can be formed within the temperatures ranging froma room temperature to 100° C. or lower; therefore, a DLC film can beeasily formed over an electroluminescent layer having low heatresistance. A DLC film can be formed by a plasma CVD method (typically,an RF plasma CVD method, a microwave CVD method, an electron cyclotronresonance (ECR) CVD method, a heat filament CVD method or the like), acombustion flame method, a sputtering method, an ion beam evaporationmethod, a laser evaporation method or the like. A hydrogen gas and ahydrocarbon system gas (for example CH₄, C₂H₂, C₆H₆ or the like) areused as a reactive gas which is used for forming the film. The reactiongas is ionized by glow discharge. The ions are accelerated to collidewith a cathode applied with negative self bias. A CN film may be formedby using a C₂H₂ gas and an N₂ gas as a reactive gas. The DLC film hashigh blocking effect on oxygen and can suppress the oxidation of theelectroluminescent layer. Accordingly, the electroluminescent layer canbe prevented from oxidizing during a subsequent sealing step.

Subsequently, a sealant is formed and sealing is performed with asealing substrate. Then, a flexible wiring substrate may be connected tothe gate wiring layer 103 to electrically connect to the exterior. Thisis the same for the source wiring layer 118.

In this embodiment mode, although the case where a light emittingelement is sealed with a glass substrate is shown, sealing treatment istreatment to protect a light emitting element from moisture. Therefore,any of a method in which a light emitting element is mechanically sealedwith a cover material, a method in which a light emitting element issealed with a heat-curable resin or an ultraviolet-light-curable resin,and a method in which a light emitting element is sealed with a thinfilm such as metal oxide, nitride or the like having high barriercapabilities, can be used. As for the cover material, glass, ceramics,plastic or metal can be used. However, when light is emitted to thecover material side, the cover material needs to have light-transmittingproperties. Enclosed space is formed by attaching the cover material tothe substrate over which the above-mentioned light emitting element isformed with a sealant such as a heat-curable resin or anultraviolet-light-curable resin and then by curing the resin with heattreatment or ultraviolet irradiation treatment. It is also effective toprovide a hydroscopic absorbent material typified by barium oxide in theenclosed space. The absorbent material may be provided over the sealantor over a partition wall or a peripheral part so as not to block lightemitted from a light emitting element. Further, it is also possible tofill the space between the cover material and the substrate over whichthe light emitting element is formed with a heat-curable resin or anultraviolet-light-curable resin. In this case, it is effective to add ahydroscopic material typified by barium oxide in the heat-curable resinor the ultraviolet-light-curable resin.

In this embodiment mode, although a single gate structure is shown for aswitching TFT, a multi-gate structure such as a double gate structuremay be also used.

As described above, in this embodiment mode, a photolithography stepusing a photomask is not employed, and thus steps can be omitted. Inaddition, a display panel can be easily manufactured by directly formingvarious patterns over the substrate with the use of a droplet dischargemethod even when a glass substrate which is in and after the fifthgeneration having 1000 mm or more on a side is used.

Moreover, regardless of the size of an outlet which discharges adroplet, a pattern having a desired width can be formed with preferablecontrollability; therefore, electric characteristics and reliability areimproved.

EMBODIMENT MODE 3

FIG. 14 and FIGS. 15A to 15C are used to describe an embodiment mode ofthe present invention. In this embodiment mode, a top gate type (aforward stagger type) thin film transistor is used as a thin filmtransistor instead of the one described in Embodiment Mode 2. Hence, therepeating description of the identical part or a part which a similarfunction is omitted. Note that FIG. 15A shows a cross-sectional viewtaken along a line A-A′ in FIG. 14, FIG. 15B shows a cross-sectionalview taken along a line B-B′ in FIG. 14, and FIG. 15C shows across-sectional view taken along a line C-C′ in FIG. 14.

A source wiring layer 118 and a power supply line 119 are formed over asubstrate 100 by discharging a composition including a conductivematerial by a droplet discharge method. Then, source or drain electrodelayers 111, 113, 115 and 116, and a conductive layer 112 are formed witha shape means of the invention. The source or drain electrode layers 111and 115, and the conductive layer 112 may be formed integrally with thesource wiring layer 118 and the power supply line 119 with a shape meansas in the case of forming the gate electrode layer 104 and the gateelectrode layer 105, since they are formed to be in contact with thesource wiring layer 118 and the power supply line 119 which are formedbefore. In this embodiment mode, the source or drain electrode layer 111is formed with a shape means before the source wiring layer 118 is fullycured, and the conductive layer 112 and the source or drain electrodelayer 115 are formed with a shape means before the power supply line 119is fully cured. When a material such as an extra fine nanotube is usedfor a shape portion, a further minute pattern can be formed.

An N-type semiconductor layer is formed over the source or drainelectrode layers 111, 113, 115 and 116 and etching is performed with amask formed of a resist or the like. The resist may be formed by adroplet discharge method. A semiconductor layer is again formed over theN-type semiconductor layer and is patterned with the use of a mask orthe like. Thus, N-type semiconductor layers 109 and 110, andsemiconductor layers 107 and 108 are formed.

Then, a gate insulating layer 106 is formed with a single layerstructure or a laminated structure by using a plasma CVD method, asputtering method or the like. As a preferable mode in particular, athree-layer laminated body of an insulating layer 106 a formed ofsilicon nitride, an insulating layer 106 b formed of silicon oxide, andan insulating layer 106 c formed of silicon nitride corresponds to thegate insulating layer.

A mask including an insulator such as a resist or polyimide is formed byusing a droplet discharge method to form through-holes 146 and 147 in apart of the gate insulating layer 106 by etching-processing with the useof the mask. Thus, a part of the source or drain electrode layers 113and 116 which are located under the gate insulating layer 106 isexposed.

A gate wiring layer 103 is formed by discharging a composition includinga conductive material. Then, gate electrode layers 104 and 105 areformed with the use of a shape means of the invention. The gateelectrode layer 104 may be formed integrally with the gate wiring layer103 with the use of a shape means as in the case of forming the sourceor drain electrode layer 111 since it is formed to be in contact withthe gate wiring layer 103 which is formed before. In this embodimentmode, the gate electrode layer 104 is formed with a shape means beforethe gate wiring layer 103 is fully cured. When a material such as anextra fine nanotube is used for a shape portion, further minute patterncan be formed. Lower resistance and improved mobility are achieved sincea width in a channel direction of the gate electrode layer 104 can bemade narrower.

In the through-hole 146 formed in the gate insulating layer 106, thegate electrode layer 105 and the source or drain electrode layer 116 areelectrically connected to each other. A capacitor element is formed ofthe gate electrode layer 105, the gate insulating layer 106 and theconductive layer 112.

A first electrode layer 117 is formed by a droplet discharge method.Naturally, the first electrode layer can be also shaped to have adesired pattern with a shape means of the invention. The first electrodelayer and the source or drain electrode layer 113 are electricallyconnected to each other in the though-hole 147 formed before.

Subsequently, an insulating layer is formed as in Embodiment Mode 2, andan electroluminescent layer and a second insulating layer are formedafter providing an opening over the first electrode layer. Further, asealant is formed and sealing is performed with a sealing substrate.Then, a flexible wiring substrate may be connected to the gate wiringlayer 103 or the source wiring layer 118. As described above, a displaypanel having a display function can be manufactured.

As described above, in this embodiment mode, steps can be omitted sincea photolithography step using a photomask is not employed. In addition,a display panel can be easily manufactured even when a glass substratewhich is in and after the fifth generation having 1000 mm or more on aside is used by directly forming various patterns over the substratewith the use of a droplet discharge method.

Moreover, regardless of the size of an outlet which discharges adroplet, a pattern having a desired width can be formed with preferablecontrollability; therefore, electrical characteristics and reliabilityare improved.

EMBODIMENT MODE 4

A thin film transistor can be formed by applying the present invention,and a display device can be formed with the use of the thin filmtransistor. In addition, when a light emitting element is used and anN-type transistor is used as a transistor which drives the lightemitting element, light emitted from the light emitting element performsany of bottom emission, top emission and dual emission. Here, FIGS. 32Ato 32C are used to describe laminated structures of a light emittingelement according to each emission.

In this embodiment mode, a channel protective type thin film transistor481 including a channel protective film to which the invention isapplied is used. The channel protective film may be formed by droppingpolyimide, polyvinyl alcohol or the like with the use of a dropletdischarge method. As a result, a photolithography step can be omitted.As the channel protective film, one kind of an inorganic material(silicon oxide, silicon nitride, silicon oxynitride, silicon nitrideoxide or the like), a photosensitive or non-photosensitive organicmaterial (an organic resin material) (polyimide, acrylic, polyamide,polyimide amide, a resist, benzocyclobutene or the like), a Low kmaterial which has a low dielectric constant, and the like; a filmincluding plural kinds thereof; a lamination layer thereof; or the likecan be used. Additionally, a material which has a skeleton formed by thebond of silicon (Si) and oxygen (O), and which includes at leasthydrogen as a substituent, or at least one of fluoride, alkyl group, andaromatic hydrocarbon as a substituent, may be used. As a manufacturingmethod, a vapor phase growth method such as a plasma CVD method or aheat CVD method, or a sputtering method can be used. A droplet dischargemethod or a printing method (a method for forming a pattern, such as ascreen printing or offset printing) can be also used. A TOF film or anSOG film obtained by an application method can be also used.

First, the case where light is emitted to the side of a substrate 480,in other words, bottom emission is performed, is described withreference to FIG. 32A. In this case, source or drain wiring 483, a firstelectrode 484, an electroluminescent layer 485, and a second electrode486 are sequentially laminated so as to be electrically connected to thetransistor 481. Next, the case where light is emitted to the sideopposite the substrate 480, in other words, top emission is performed,is described with reference to FIG. 32B. Source or drain wiring 462, afirst electrode 463, an electroluminescent layer 464 and a secondelectrode 465 which are electrically connected to the transistor 481 aresequentially laminated. According to the above-mentioned structure, evenwhen the first electrode 463 transmits light, the light is reflected bythe source or drain wiring 462 and emitted to the side opposite thesubstrate 480. Note that in this structure, it is not necessary to use amaterial having light-transmitting properties for the first electrode463. Lastly, the case where light is emitted to both the side of thesubstrate 480 and the opposite side thereof, in other words, dualemission is performed, is described with reference to FIG. 32C. Sourceor drain wiring 471, a first electrode 472, an electroluminescent layer473 and a second electrode 474 which are electrically connected to thetransistor 481 are sequentially laminated. At this time, when both thefirst electrode 472 and the second electrode 474 are formed of amaterial having light-transmitting properties, or formed to have a filmthicknesses which can transmit light, dual emission can be achieved.

A light emitting element has a structure in which the electroluminescentlayer is sandwiched between the first electrode and the secondelectrode. It is necessary to select a material for the first electrodeand the second electrode considering a work function. The firstelectrode and the second electrode can be either an anode or a cathodedepending on a pixel structure. In this embodiment mode, it ispreferable to make the first electrode a cathode, and the secondelectrode an anode, since the polarity of a drive TFT is an n-channeltype. In addition, when polarity of the drive TFT is a p-channel type,it is preferable to make the first electrode an anode, and the secondelectrode a cathode.

When the first electrode is an anode, in the electroluminescent layer,it is preferable to laminate an HIL (a hole injection layer), an HTL (ahole transport layer), an EML (a light emitting layer), an ETL (anelectron transport layer), and an EIL (an electron injection layer) inorder from the anode side. When the first electrode is a cathode, it ispreferable to laminate layers adversely, namely, laminate an EIL (anelectron injection layer), an ETL (an electron transport layer), an EML(a light emitting layer), an HTL (a hole transport layer), an HIL (ahole injection layer), and a cathode which is the second electrode inorder from the cathode side. Additionally, the electroluminescent layercan be also formed with a single layer structure or a combinedstructure, in addition to a laminated structure.

As the eletcroluminescent layer, materials each indicates luminescenceof red (R), green (G) and blue (B) are selectively formed by anevaporation method using an evaporation mask or the like for each. Thematerials (low molecular weight materials or high molecular weightmaterials or the like) each indicates luminescence of red (R), green (G)and blue (B) can be formed by a droplet discharge method as a colorfilter. In this case, it is preferable since RGB can be separatelycolored without using a mask.

Specifically, CuPc or PEDOT is used as the HIL; α-NPD, as the HTL; BCPor Alq₃, as the ETL; BCP:Li or CaF₂, as the EIL, respectively. When ITOor ITSO having light-transmitting properties is used for the secondelectrode in the case of top emission type, BzOS—Li in which Li is addedto benzoxazole derivative, or the like can be used. In addition, Alq₃doped with a dopant corresponding to respective luminescence colors ofR, G and B (DCM or the like in the case of R, and DMQD or the like inthe case of G) may be used as the EML, for example.

Note that the electroluminescent layer is not limited to the abovematerial. For example, a hole injectability property can be enhanced byco-evaporating oxide such as molybdenum oxide (MoO_(X): X=2 to 3) andα-NPD or rubrene instead of using CuPc or PEDOT. An organic material(including a low molecular weight material or a high molecular weightmaterial) or a composite material of an organic material and aninorganic material can be used as the material of the electroluminescentlayer.

In addition, a color filter may be formed over a counter substrate ofthe substrate 480, although it is not shown in FIGS. 32A to 32C. Thecolor filter can be formed by a droplet discharge method; in that case,photoplasma treatment or the like can be performed as theabove-mentioned base pretreatment. The color filter can be formed in adesired pattern with favorable adhesion due to the base film of theinvention. High-definition display can be performed by using the colorfilter. This is because the color filter can adjust a broad peak tosharp one in each emission spectrum of RGB.

The case of forming materials showing each light emission of RGB isdescribed hereinabove; however, full color display can be performed alsoby forming a material showing light emission of single color andcombining the material with a color filter or a color conversion layer.For example, in the case of forming an electroluminescent layer showingwhite or orange light emission, full color display can be performed byseparately providing a color filter, a color conversion layer, or acombination of a color filter and a color conversion layer. For example,the color filter or the color conversion layer may be formed over asecond substrate (a sealing substrate), and then, be attached to thesubstrate. As described above, the material showing light emission ofsingle color, the color filter, and the color conversion layer can allbe formed by a droplet discharge method.

Naturally, display of single color light emission may be performed. Forexample, an area color type light emitting display device may be formedby using single color light emission. A passive matrix display portionis suitable for the area color type and can display mainly charactersand symbols.

A material having a low work function can be used for the cathode in theabove-mentioned structure; for example, Ca, Al, CaF, MgAg, AlLi, or thelike is preferable. The electroluminescent layer may be any of a singlelayer type, a lamination layer type, and a mixed type having nointerface between layers. Any of the following materials can be used: asinglet material, a triplet material, a combined material thereof, anorganic material including a low molecular weight material, a highmolecular weight material, and an intermediate molecular weightmaterial, an inorganic material typified by molybdenum oxide which issuperior in an electron injection property, or the like, and a compositematerial of an organic material and an inorganic material. The firstelectrodes 484, 463, and 472 are formed by using a transparentconductive film which transmits light; for example, a transparentconductive film in which indium oxide is mixed with zinc oxide (ZnO) offrom 2% to 20% as well as ITO or ITSO is used. Note that plasmatreatment in an oxygen atmosphere or heat treatment in a vacuumatmosphere is preferably performed before forming the first electrodes484, 463, and 472. A partition wall (also referred to as a bank) isformed by using a material containing silicon, an organic material, or acompound material. In addition, a porous film may be used. However, itis preferable to form the partition wall by using a photosensitive ornon-photosensitive material such as acrylic or polyimide, since a sideface thereof becomes a shape in which a radius of curvature continuouslychanges and an upper-layer thin film is formed without break. Thisembodiment mode can be freely combined with the above embodiment mode.

EMBODIMENT MODE 5

In a display panel manufactured according to Embodiment Modes 2 to 4, ascanning line driver circuit can be formed over a substrate 3700 byforming a semiconductor layer of an SAS as described in FIG. 31.

FIG. 22 shows a block diagram of a scanning line driver circuitincluding n-channel type TFTs using an SAS in which electricfield-effect mobility of from 1 cm²/V·sec to 15 cm²/V·sec can beobtained.

A block shown in reference numeral 500 corresponds to a pulse outputcircuit outputting a sampling pulse for one stage in FIG. 22, and ashift register includes n pieces of pulse output circuit. Referencenumeral 541 denotes a buffer circuit, and a pixel 542 is connected atthe end thereof.

FIG. 23 shows a specific structure of the pulse output circuit 500, andthe circuit includes n-channel type TFTs 601 to 613. At this time, thesize of the TFTs may be decided in consideration of operatingcharacteristics of the n-channel type TFTs using an SAS. For example,when a channel length is set to be 8 μm, the channel width can be setranging from 10 μm to 80 μm.

In addition, FIG. 24 shows a specific structure of the buffer circuit541. The buffer circuit includes n-channel type TFTs 620 to 635 in thesame manner. At this time, the size of the TFTs may be decided inconsideration of operating characteristics of the n-channel type TFTsusing an SAS. For example, when a channel length is set to be 10 μm, thechannel width can be set ranging from 10 μm to 1800 μm.

It is necessary to connect the TFTs with one another by wirings torealize such a circuit, and FIG. 25 shows a structure example of wiringsin the case thereof. FIG. 25 shows a state in which a gate electrodelayer 104, a gate insulating layer 106 (a three-layer laminated body ofan insulating layer 106 a formed of silicon nitride, an insulating layer106 b formed of silicon oxide, and an insulating layer 106 c formed ofsilicon nitride), a semiconductor layer 107 formed of an SAS, an N-typesemiconductor layer 109 which forms a source and a drain, and source ordrain electrode layers 111 and 116 are formed. In this case, connectionwiring layers 170, 171 and 172 are formed over a substrate 100 in thesame step with the gate electrode layer 104. Then, a part of the gateinsulating layer is etching-processed so that the connection wiringlayers 170, 171 and 172 are exposed, and various kinds of circuits canbe realized by appropriately connecting the TFTs with the source ordrain electrode layers 111 and 116, and a connection wiring layer 173formed in the same step thereof.

EMBODIMENT MODE 6

A mode in which a driver circuit for driving is mounted on a displaypanel manufactured according to Embodiment Modes 2 to 4 is described.

First, a display device to which a COG method is applied is explainedwith reference to FIG. 31. A pixel portion 3701 displaying informationsuch as a character or an image, and a scanning line driver circuit 3702are provided over a substrate 3700. The substrate over which a pluralityof driver circuits are provided is separated into rectangles. Drivercircuits after separation (hereinafter referred to as “a driver IC”)3705 a and 3705 b are mounted over the substrate 3700. FIG. 31 shows amode in which a plurality of driver ICs 3705 a and 3705 b, and tapes3704 a and 3704 b mounted on the ends of the driver ICs 3705 a and 3705b are mounted. In addition, the separation size is made approximatelysame as a side of a signal line side in the pixel portion, and a tapemay be mounted on an end of a single driver IC.

Alternatively, a TAB method may be applied, and in this case, aplurality of tapes are attached and driver ICs may be mounted on thetapes. As in the case of a COG method, single driver IC may be mountedon a single tape, and in this case, a metal piece, or the like to fixthe driver IC may be attached at the same time in view of an intensitymatter.

As for these driver ICs mounted on display panels, a plurality of thedriver ICs may be mounted on a rectangular substrate having 300 mm to1000 mm or more on a side in view of improving productivity.

In other words, a plurality of circuit patterns, in which a drivercircuit portion and an input and output terminal are one unit, areformed over a substrate, and separated and obtained last. The length ofa long side of a driver IC may be formed to be from 15 mm to 80 mm; anda short side, from 1 mm to 6 mm, which forms a rectangular shape, inconsideration of the length of a side length of a pixel portion or apixel pitch. Alternatively, it may be formed to have the length of aside of the pixel region, or the sum of a side of the pixel portion anda side of the driver circuit.

The advantage of the external dimension of a driver IC compared with anIC chip is the length of a long side. When a driver IC in which a longside is formed to be from 15 mm to 80 mm is used, less IC chips arerequired to mount correspondingly to a pixel portion; therefore, amanufacturing yield can be enhanced. When a driver IC is formed over aglass substrate, productivity is not impaired since it is not limited bya shape of a substrate to be used as a body. This is a significantadvantage compared with the case where IC chips are obtained from acircular silicon wafer.

In FIG. 31, the driver ICs 3705 a and 3705 b over which a driver circuitis formed are mounted in a region outside the pixel portion 3701. Thesedriver ICs 3705 a and 3705 b are signal line driver circuits. To form apixel portion corresponding to RCB full colors, 3072 signal lines arerequired for an XGA class, and 4800 signal lines are required for a UXGAclass. The signal lines of such a number forms a leading out line bybeing divided into several blocks at an edge of the pixel region 3701and is gathered in accordance with a pitch of an output terminal of thedriver ICs 3705 a and 3705 b.

The driver ICs are preferably formed of a crystalline semiconductorformed over a substrate. The crystalline semiconductor is preferable tobe formed by being irradiated with a continuous-wave laser. Therefore, acontinuous-wave solid state laser or gas laser is used as an oscillatorin which the laser is generated. There are few crystal defects when acontinuous-wave laser is used. As a result, a transistor can bemanufactured by using a polycrystalline semiconductor layer with a largegrain size. In addition, high-speed driving is possible since mobilityor a response speed is favorable, and it is possible to further improvean operating frequency of an element than that of the conventionalelement; therefore, high reliability can be obtained since there are fewproperty variations. Note that a channel length direction of atransistor and a scanning direction of laser light may be accorded witheach other to further improve an operating frequency. This is becausethe highest mobility can be obtained when a channel length direction ofa transistor and a scanning direction of laser light with respect to asubstrate are almost parallel (preferably, from −30° to 30°) in a stepof laser crystallization by a continuous-wave laser. A channel lengthdirection coincides with a direction of current flowing in a channelform region, in other words, a direction in which an electric chargemoves. The transistor thus manufactured has an active layer including apolycrystalline semiconductor layer in which a crystal grain is extendedin a channel direction, and this means that a crystal grain boundary isformed almost along a channel direction.

In carrying out laser crystallization, it is preferable to narrow downthe laser light largely, and a beam spot thereof preferably has a widthof approximately from 1 mm to 3 mm of which width is same as that of ashort side of the driver ICs. In addition, in order to ensure an objectto be irradiated an enough and effective energy density, an irradiatedregion of the laser light is preferably a linear shape. However, alinear shape here does not refer to a line in a proper sense, but refersto a rectangle or an oblong with a large aspect ratio. For example, thelinear shape refers to a rectangle or an oblong with an aspect ratio of2 or more (preferably from 10 to 10000). Accordingly, productivity canbe improved by identifying a width of a beam spot of the laser lightwith that of a minor axis of the driver ICs.

In FIG. 31, a mode in which the scanning line driver circuit isintegrally formed with the pixel portion and the driver ICs are mountedas a signal line driver circuit is shown. However, the present inventionis not limited to this mode, and the driver ICs may be mounted as both ascanning line driver circuit and a signal line driver circuit. In thatcase, it is preferable to differentiate a specification of the driverICs to be used on the scanning line and signal line side.

In the pixel portion 3701, the signal line and the scanning line areintersected to form a matrix and a transistor is arranged in accordancewith each intersection. A TFT having a structure in which a channelportion is formed from an amorphous semiconductor or a semi-amorphoussemiconductor can be used as the transistor arranged in the pixelportion 3701 in the invention. An amorphous semiconductor is formed by amethod such as a plasma CVD method or a sputtering method. It ispossible to form a semi-amorphous semiconductor at temperatures of 300°C. or lower with a plasma CVD method. A film thickness necessary to forma transistor is formed in a short time even in the case of anon-alkaline glass substrate of an external size of, for example, 550mm×650 mm. The feature of such a manufacturing technique is effective inmanufacturing a display device of a large-sized screen. In addition, asemi-amorphous TFT can obtain electric field-effect mobility of 2cm²/V·sec to 15 cm²/V·sec by constituting a channel form region with anSAS. Therefore, this TFT can be used as a switching element of pixelsand as an element which constitutes the scanning line driver circuit.Accordingly, a display panel in which a system-on-panal is achieved, canbe manufacture.

FIG. 31 is shown based on that the scanning line driver circuit isintegrally formed over the substrate by using the TFT in which asemiconductor layer is formed of an SAS. When a TFT in which asemiconductor layer is formed of an SAS is used, the drive ICs may bemounted on both the scanning line driver circuit and the signal linedriver circuit.

In that case, it is preferable to differentiate a specification of thedriver ICs to be used in the scanning line and signal line side. Forexample, although the withstand pressure of approximately 30 V isrequired for a transistor constituting a scanning line driver IC, adrive frequency is 100 kHz or less, and thus high-speed operation is notrelatively required. Therefore, it is preferable to set thechannel-length (L) of a transistor constituting the scanning line driversufficiently long. On the other hand, in a transistor of the signal linedriver IC, although the withstand pressure of approximately of 12 V issufficient, a drive frequency is about 3V and 65 MHz, and thushigh-speed operation is required. Accordingly, it is preferable to setthe channel length of a transistor constituting a driver in micrometer.

The method for mounting a driver IC is not particularly limited, and aCOG method, a wire bonding method, or a TAB method, which are knownmethods can be used.

The thickness of the drive IC is made same as that of a countersubstrate; therefore, the heights thereof are made approximately thesame contributing to thinning a display device as a whole. Bymanufacturing each substrate of the same material, heat stress is notgenerated even when a change in temperature is generated in the displaydevice and the characteristics of a circuit manufactured of the TFT arenot impaired. Additionally, by mounting longer driver ICs than IC chipsto the driver circuit as shown in this embodiment mode, the number ofthe driver ICs mounted on one pixel portion can be reduced.

As mentioned above, the driver circuit can be incorporated into adisplay panel.

EMBODIMENT MODE 7

A structure of a pixel of a display panel shown in this embodiment isdescribed with reference to equivalent circuit diagrams shown in FIGS.26A to 26F.

In a pixel shown in FIG. 26A, a signal line 410 and power supply lines411 to 413 are arranged in columns, and a scanning line 414 is arrangedin a row. The pixel also includes a switching TFT 401, a driver TFT 403,a current controlling TFT 404, a capacitor element 402, and alight-emitting element 405.

A pixel shown in FIG. 26C has the same structure as the one shown inFIG. 26A, except that a gate electrode of the driver TFT 403 isconnected to the power supply line 412 arranged in a row. Both pixels inFIGS. 26A and 26C show the same equivalent circuit diagrams. However,each power supply line is formed of conductive layers in differentlayers in between the cases where the power supply line 412 is arrangedin a column (FIG. 26A) and where the power supply line 412 is arrangedin a row (FIG. 26C). The two pixels are each shown in FIGS. 26A and 26Cin order to show that layers in which a wiring connected to the gateelectrode of the driver TFT 403 is formed are different in between FIGS.26A and 26C.

In both FIGS. 26A and 26C, the driver TFT 403 and the currentcontrolling TFT 404 are connected in series in the pixel, and the ratioof the channel length L₃/the channel width W₃ of the driver TFT 403 tothe channel length L₄/the channel width W₄ of the current controllingTFT 404 is set as L₃/W₃:L₄/W₄=5 to 6000:1. For example, when L₃, W₃, L₄,and W₄ are 500 μm, 3 μm, 3 μm, and 100 μm, respectively.

The driver TFT 403 is operated in a saturation region and controls theamount of current flowing in the light emitting element 405, whereas thecurrent controlling TFT 404 is operated in a linear region and controlsa current supplied to the light emitting element 405. The TFTs 403 and404 preferably have the same conductivity in view of the manufacturingprocess. For the driver TFT 403, a depletion type TFT may be usedinstead of an enhancement type TFT. According to the invention havingthe above structure, slight variations in V_(GS) of the currentcontrolling TFT 404 does not affect the amount of current flowing in thelight emitting element 405, since the current controlling TFT 404 isoperated in a linear region. That is, the amount of current flowing inthe light emitting element 405 is determined by the driver TFT 403operated in a saturation region. Accordingly, it is possible to providea display device in which image quality is improved by improvingvariations in luminance of the light emitting element due to variationof the TFT properties.

The switching TFT 401 of pixels shown in FIGS. 26A to 26D controls avideo signal input to the pixel. When the switching TFT 401 is turned ONand a video signal is inputted to the pixel, the video signal is held inthe capacitor element 402. Although the pixel includes the capacitorelement 402 in FIGS. 15A to 15D, the invention is not limited thereto.When a gate capacitance or the like can serve as a capacitor for holdinga video signal, the capacitor element 402 is not necessarily provided.

The light emitting element 405 has a structure in which anelectroluminescent layer is sandwiched between a pair of electrodes. Apixel electrode and an opposing electrode (an anode and a cathode) havea potential difference therebetween so that a forward bias voltage isapplied. The electroluminescent layer is formed of wide range ofmaterials such as an organic material, an inorganic material. Theluminescence in the electroluminescent layer includes luminescence thatis generated when an excited singlet state returns to a ground state(fluorescence) and luminescence that is generated when an exited tripletstate returns to a ground state (phosphorescence).

A pixel shown in FIG. 26B has the same structure as the one shown inFIG. 26A, except that a TFT 406 and a scanning line 415 are added.Similarly, a pixel shown in FIG. 26D has the same structure as the oneshown in FIG. 26C, except that a TFT 406 and a scanning line 415 areadded.

The TFT 406 is controlled to be ON/OFF by the added scanning line 415.When the TFT 406 is turned ON, charges held in the capacitor element 402are discharged, thereby turning the TFT 404 OFF. That is, supply of acurrent to the light emitting element 405 can be forcibly stopped byproviding the TFT 406. Therefore, a lighting period can startsimultaneously with or shortly after a writing period starts beforesignals are written into all the pixels by adopting the structures shownin FIGS. 26B and 26D, thus, the duty ratio can be improved.

In a pixel shown in FIG. 26E, a signal line 450 and power supply lines451 and 452 are arranged in columns, and a scanning line 453 is arrangedin a row. The pixel further includes a switching TFT 441, a driver TFT443, a capacitor element 442, and a light emitting element 444. A pixelshown in FIG. 26F has the same structure as the one shown in FIG. 26E,except that a TFT 445 and a scanning line 454 are added. It is to benoted that the structure of FIG. 26F also allows a duty ratio to beimproved by providing the TFT 445.

EMBODIMENT MODE 8

One mode in which a protective diode is provided for a scanning lineinput terminal portion and a signal line input terminal portion isexplained with reference to FIG. 27. TFTs 501 and 502 are provided for apixel 3400 in FIG. 27. The TFT has the similar structure as the oneshown in Embodiment Mode 2.

Protective diodes 561 and 562 are provided for the signal line inputterminal portion. These protective diodes are manufactured in the samestep as that of the TFTs 501 or 502. The protective diodes 561 and 562are operated as a diode by connecting a gate to one of a drain and asource. FIG. 28 shows an equivalent circuit diagram such as a top viewshown in FIG. 27.

The protective diode 561 includes a gate electrode layer 550, asemiconductor layer 551, an insulating layer for channel protection 552,and a wiring layer 553. The protective diode 562 has the same structure.Common potential lines 554 and 555 connecting to this protective diodeare formed in the same layer as that of the gate electrode. Therefore,it is necessary to form a contact hole in a gate insulating layer toelectrically connect to the wiring layer 553.

A mask layer may be formed by a droplet discharge method and anetching-process may be carried out to form a contact hole in the gateinsulating layer. In this case, when an etching-process by atmosphericpressure discharge is applied, a local discharge process is alsopossible, and it does not need to form a mask over the entire surface ofa substrate.

A signal wiring layer 237 is formed in the same layer as that of asource or drain wiring layer 212 and has a structure in which the signalwiring 237 connected thereto is connected to a source side or a drainside.

A scanning signal line input terminal portion has a similar structure.According to the present invention, the protective diodes provided in aninput stage can be formed at the same time. Note that the position ofdepositing a protective diode is not limited to this embodiment mode andcan be also provided between a driver circuit and a pixel.

EMBODIMENT MODE 9

FIG. 20 shows an example of constituting an EL display module by using aTFT substrate 2800 manufactured by a droplet discharge method. In thefigure, a pixel portion including a pixel is formed over the TFTsubstrate 2800.

In FIG. 20, a TFT which is same as the one formed in the pixel, or aprotective circuit portion 2801 which is operated same as a diode byconnecting a gate of the TFT and either a source or a drain is providedoutside the pixel portion, and between a driver circuit and the pixel. Adriver IC formed of a monocrystal semiconductor, a stick driver ICformed of a polycrystalline semiconductor film over a glass substrate, adriver circuit formed of an SAS, or the like are applied to a drivercircuit 2809.

The TFT substrate 2800 is fixed to a sealing substrate 2820 with spacers2806 a and 2806 b formed by a droplet discharge method therebetween. Thespacers are preferably provided to keep the distance between twosubstrates constant, even when the substrates are thin and the pixelportion becomes larger in size. The gap between the TFT substrate 2800and the sealing substrate 2820 over light emitting elements 2804 and2805 may be filled with a resin material having light-transmittingproperties and then cured, or may be filled with anhydrous nitrogen oran inert gas.

In FIG. 20, the case where the light emitting elements 2804 and 2805have a top emission type structure is shown, and it is a structure inwhich light is emitted in a direction indicated by an arrow shown in thefigure. Each pixel can perform multi-color display by making each pixelhave different luminescent colors of red, green and blue. Additionally,color purity of light emission emitted to the exterior can be enhancedby forming colored layers 2807 a, 2807 b and 2807 c corresponding toeach color on the sealing substrate 2820 side. In addition, the pixelmay be made a white color light emitting element, and the white colorlight emitting element can be combined with the colored layers 2807 a,2807 b and 2807 c.

The driver circuit 2809 is connected to a scanning line or a signal lineconnection terminal provided in an edge of the TFT substrate 2800 with awiring substrate 2810. Alternatively, a heat pipe 2813 and an emissionplate 2812 may provided to be in contact with or adjacent to the TFTsubstrate 2800, which is a structure to enhance a heat release effect.

In FIG. 20, although a top emission EL module is shown, a bottomemission structure may be also employed by changing the structure of alight emitting element or the position of an external circuit substrate.When it is a top emission type structure, an insulating layer to be apartition wall ay colored to use as black matrix. The partition wall canbe formed by a droplet discharge method, and it can be formed by mixingcarbon black or the like into a resin material such as polyimide, or bylaminating thereof.

In the TFT substrate 2800, a sealing structure may be formed byattaching a resin film to the side where the pixel portion is formedwith the use of a sealant or an adhesive resin. On the surface of theresin film, a gas barrier film which prevents vapor from transmittingmay be preferably formed. By applying a film sealing structure, adisplay device can be made further thinner and lighter.

EMBODIMENT MODE 10

A TV set can be completed by using a display device formed according tothe present invention. FIG. 19 shows a block diagram which shows a mainstructure of a TV set. In a display panel, there are a case where only apixel portion is formed, and a scanning line driver circuit and a signalline driver circuit are mounted by a TAB method as a structure as shownin FIG. 29, a case where the pixel portion, and the scanning line drivercircuit and the signal line driver circuit at the periphery of the pixelportion are mounted by a COG method as a structure as shown in FIG. 30,and a case where the TFT is formed of an SAS, the pixel portion and thescanning line driver circuit are integrally formed over the substrate,and the signal line derive circuit is separately mounted as the driverIC as shown in FIG. 31. Any of the modes can be applied.

Another external circuit structure may include a video signal amplifiercircuit 805 which amplifies a video signal among signals received by atuner 804, a video signal processing circuit 806 which converts a signalto be outputted therefrom into a chrominance signal corresponding toeach color of red, green, and blue, a control circuit 807 which convertsthe video signal into an input specification of a driver IC, and thelike on an input side of a video signal. The control circuit 807 outputsa signal to both a scanning line side and a signal line side. In thecase of digital driving, a signal dividing circuit 808 may be providedon the signal line side, and an input digital signal may be divided intom parts and be supplied.

An audio signal among signals received by the tuner 804 is transmittedto an audio signal amplifier circuit 809 and is supplied to a speaker813 through an audio signal processing circuit 810 to be outputted. Acontrol circuit 811 receives control information on a receiving station(receive frequency) or volume from an input portion 812 and transmitsthe signal to the tuner 804 and the audio signal processing circuit 810.

A TV set can be completed by incorporating the module into a chassis2001 as shown in FIG. 17. When an EL display module as shown in FIG. 20is used, an EL television set can be completed, and when a liquidcrystal display module as shown in FIG. 21 is used, a liquid crystaltelevision can be completed. A main display screen 2003 is formed byusing the display module, and speaker portions 2009, an operationswitch, and the like may be provided as an attachment. Thus, a TV setcan be completed according to the present invention.

In addition, in a TV set, reflected light of light entering from outsidemay be blocked by using a wave plate and a polarizing plate. Aquarter-wave plate¥a half-wave plate are used as the wave plate, and maybe designed to be able to control light. A module has a laminatedstructure of a TFT element substrate¥ a light emitting element¥ asealing substrate (sealant)¥ a wave plate (a quarter-wave plate¥ ahalf-wave plate)¥ a polarizing plate, and light emitted from a lightemitting element passes therethrought and is emitted outside on apolarizing plate side. The wave plate and the polarizing plate may beprovided on an emitted side of light. In the case of a dual emissionlight emitting display device which emits light on both sides, the waveplate and the polarizing plate can be provided on both sides. Inaddition, an anti-reflective film may be provided outside the polarizingplate. This makes it possible to display a high-definition preciseimage.

A display panel 2002 utilizing a liquid crystal or an EL element isincorporated in the chassis 2001. Not only can ordinary TV broadcastingbe received by a receiver 2005, but also one-way information andtelecommunication (from a transmitter to a receiver) or two-wayinformation and telecommunication (between a transmitter and a receiveror between receivers) can be achieved by connecting to a communicationnetwork with or without a wire through a modem 2004. The TV set can beoperated by a switch incorporated in the chassis or aseparately-provided remote control unit 2006, and a display portion 2007showing information to be outputted may be included in the remotecontrol unit.

Further, also the TV set may be made to have a structure which displayschannels or volume by forming a sub screen 2008 using a second displaypanel as well as a main screen 2003. In this structure, the main screen2003 may be formed by using an EL display panel having wide view angleand the sub screen may be formed by using a liquid crystal display panelwhich allows display at low energy consumption. Further, in the case ofputting priority on lower power consumption, the main screen 2003 may beformed by using a liquid crystal display panel, the sub screen 2008 maybe formed by using an EL display panel, and then, the sub screen can beturned on and off. A highly display device can be formed by applying theinvention even when such a large-sized substrate is used, and thus, alarge number of TFTs or electronic parts are used.

Of course, the invention is not limited to a TV set and can be appliedto various use applications particularly as a large-area display mediumsuch as an information display board in a train station, an airport, orthe like, or an advertisement display board in the street as well as amonitor of a personal computer.

EMBODIMENT MODE 11

Various light emitting display devices can be manufactured by applyingthe present invention. That is to say, the invention can be applied tovarious electronic devices in which the light emitting display devicesare incorporated in a display portion.

Such electronic devices can be given as follows: a camera such as avideo camera, a digital camera or the like; a projector; a head mounteddisplay (a goggle type display); a car navigation system; a car stereo;a personal computer; a game machine; a personal digital assistance (amobile computer, a cellular phone, an electronic book, or the like); animage reproducing device including a recording medium (specifically, adevice capable of processing data in a recording medium such as aDigital Versatile Disc (DVD) and having a display that can display theimage of the data); and the like. Examples thereof are shown in FIGS.18A to 18D.

FIG. 18A shows a personal computer, which includes a main body 2101, achassis 2102, a display portion 2103, a keyboard 2104, an externalconnection port 2105, a pointing mouse 2106, and the like. The inventionis applied to manufacturing the display portion 2103. When the inventionis applied, a highly reliable high-quality image can be displayed evenif the personal computer is miniaturized and a wiring or the likebecomes precise.

FIG. 18B shows an image reproducing device including a recording medium(specifically, a DVD reproducing device), which includes a main body2201, a chassis 2202, a display portion A 2203, a display portion B2204, a recording medium (a DVD or the like) reading portion 2205,operation keys 2206, speaker portions 2207, and the like. The displayportion A 2203 mainly displays image information, and the displayportion B 2204 mainly displays character information. The invention isapplied to manufacturing the display portion A 2203 and the displayportion B 2204. When the invention is applied, a highly reliablehigh-quality image can be displayed even if the image reproducing deviceis miniaturized and a wiring or the like becomes precise.

FIG. 18C shows a cellular phone, which includes a main body 2301, anaudio output portion 2302, an audio input portion 2303, a displayportion 2304, operation switches 2305, an antenna 2306, and the like. Ahighly reliable high-quality image can be displayed even in a cellularphone which is miniaturized and in which a wiring or the like becomesprecise by applying the display device manufactured according to theinvention to the display portion 2304.

FIG. 18D shows a video camera, which includes a main body 2401, adisplay portion 2402, a chassis 2403, an external connection port 2404,a remote control receiving portion 2405, an image receiving portion2406, a battery 2407, an audio input portion 2408, operation keys 2409,and the like. The invention can be applied to the display portion 2402.A highly reliable high-quality image can be displayed even in a videocamera which is miniaturized and in which a wiring or the like becomesprecise by applying the display device manufactured according to theinvention to the display portion 2402. This embodiment can be freelycombined with the above embodiment modes.

1. A droplet discharge device comprising: discharge means fordischarging a composition including a pattern forming material; andshape means for shaping the shape of the composition before thecomposition is attached to a formation region, in which the shape meansis provided between the discharge means and the formation region.
 2. Adroplet discharge device comprising: discharge means for discharging acomposition including a pattern forming material; and shape means forshaping the shape of the composition after the composition is attachedto a formation region.
 3. A droplet discharge device according to claim1 or claim 2, wherein the shape means is provided to be in contact withan outlet of the droplet discharge means.
 4. A droplet discharge deviceaccording to claim 1 or claim 2, wherein the shape means has a shapeportion, and the shape portion has a needle shape.
 5. A dropletdischarge device according to claim 1 or claim 2, wherein the shapemeans has a shape portion, and the shape portion has a columnar shape ora plate shape.
 6. A droplet discharge device according to claim 1 orclaim 2, wherein the shape means has a shape portion, and the shapeportion has a tube shape.
 7. A method for forming a pattern, wherein acomposition including a pattern forming material is discharged toward aformation region, and a pattern is selectively formed by shaping theshape of the composition before the composition is attached to theformation region.
 8. A method for forming a pattern, wherein acomposition including a pattern forming material is discharged toward aformation region, and a pattern is selectively formed by shaping theshape of the composition after the composition is attached to theformation region and before the composition is cured.
 9. A method forforming a pattern according to claim 7 or claim 8, wherein the shape ofthe composition is shaped with a needle shape object for shaping.
 10. Amethod for forming a pattern according to claim 7 or claim 8, whereinthe shape of the composition is shaped with a columnar shape or plateshape object for shaping.
 11. A method for forming a pattern accordingto claim 7 or claim 8, wherein the pattern forming material is formed byusing silver, gold, copper or indium tin oxide. 12-19. (canceled)
 20. ATV set, wherein a display screen image is comprised of a display devicecomprising: a semiconductor layer; a wiring; and an electrode, whereinthe wiring and the electrode are formed by discharging a compositionincluding a conductive material over a formation region, shaping a partof the shape of the composition, and selectively enlarging thecomposition.